Okay, first a few things about me:
-I am a college student with limited funds
-I shoot mostly skimboarding
-My current setup is a canon 300D digital rebel and a sigma 70-200 f/2.8 lens
-I currently have a minimum wage job, the main reason being to save up for better gear

as I am starting to get really refined to how I shoot skimboarding I am starting to realize a few problems that I have with my digital rebel.
-AI servo only works in sports mode
-continuous shooting only works in sports mode
-there is a max of four consecutive shots

I find the deal with consecutive shots especially annoying when I am shooting barrel seqiences were you really need the extra internal buffer.

So, I want to upgrade, either to a 10D or 20D. I am ruiling out the rebel xt because it is too small to fit comfrtable in my hands.

So my question is this: should I look to buy a used 10D on ebay or some other place, or should I save up the extra $500 to buy a new 20D? would it be worth it? Is the 20D that much better?

This is just my opinion, take it as you like, but have you thought about going back to film,
if you want to be able to shoot a rapid succession of pics, you can't beat film(unless you want to spend 4 grand or more) I started with a canon film, then went to a 10d after I wore the film camera out, and after finding out it limitations and quirks, I bought a used EOS 3 for about 600Canadian(400us), with a warranty, that is in perfect working order and has no buffer limitations, no white balance(which I would imagine would be a pain with the water).
I went through a roll of fuji36/400iso before I knew whats whats! Almost 5 frames a second till the roll is done, without the booster, with bumps it to almost 9 a second. But on a limited budget, it may be worth a try!

Gimp makes an excellent point!

To address your question though, you need to figure out if you NEED or WANT the upgraded features. Frankly, I think at this point the 20D is a better buy at 1300 (1200 with a current rebate) plus/minus fifty bucks depending on where you get it. The 9 shot buffer on the 10D goes just as quickly as the 4 shot on yours, and the writing speed is atrocious.

Gimp makes an excellent point!

To address your question though, you need to figure out if you NEED or WANT the upgraded features. Frankly, I think at this point the 20D is a better buy at 1300 (1200 with a current rebate) plus/minus fifty bucks depending on where you get it. The 9 shot buffer on the 10D goes just as quickly as the 4 shot on yours, and the writing speed is atrocious.

Well, since I'm not usually paid for my shots, I suppose that want the features as opposed to need them. I don't want to shoot film for this. Skimming and surfing require sooo many shots to be taken to get a good one. Digital is definitely where it's at for what I do. I don't even need that many more shots, and the 9 would most likely suffice. But, the 20D is an overall better camera. Or is it? I'm just wondering if it's worth the extra $500. keep in mind that 500 is a LOT for a college student such as myself.

That would depend on your thinking now.
I go to university in Canada, so I know what its like to have a tight bank account.
But, whenever I buy something, I always buy the best. I save my dollar or two here and there, but later spend it on something I consider high quality. Sure I'm not a professional and I dont really need the extra quality, but I usually buy things that will give me joy for years to come rather than upgrade along the way.
For me, I got a Leica M4 instead of an M2, which ended up costing me quite a bit more, but I wanted the quick load and angled rewinder. I could have settled for a pre-ASPH 35mm, but then I went for the ASPH for the extra resolution and flatness of field (although I ended up getting one for the same price of a pre-ASPH ^_^). Instead of saving my money on these "toys", I end up saving on a meal (always coupons or cook) and clothes. My friends end up getting the $100 pair jeans or $75 shirts. I just bought a great dressy shirt for $10 and another cool dressy shirt (top quality) for $25 (cdn funds) from a crazy sale that ended up giving me about 75% off. Many people I know just would just end up buying at regular price. It just depends where your priorities are.

I would stay with your 300D and get the wasia hack for the firmware to unlock AI Servo in all of the creative modes. It also unlocks continuous shooting.
If you really feel the need for more and faster continuous shooting, then I would stay away from the 10D because as Sebastian said, the 10Ds write time is really slow, and the 20D offers more fps and much faster write time. The 20D definitely improves continuous shooting.
I have been able to get some decent multi frame sequences of snowboarders with my 10D though. I think the 300D with the wasia hack would be nearly as capable.

I've heard of the hack and it sounds interesting, but would it improve the continuous shooting?

The 300D hack basically unlocks it to being nearly a 10D equivalent. Just remember that the guts of it is is basically the 10D with things turned off. Look at dpreview.com and do a search for the hack info/opinions there.

Get the 20D, It will improve you're odds of getting a saleable photo, It has a magneseium body (You know you want it!) And promise youreself you will sell 100 prints @ $5.00 profit, Or 10 prints @ $50.00 profit.
Ok, seriously and honestly, I think that upgrading the rebel is a poor cheap option, buying a 10D is a waste, but getting the 20D just makes sense!
BTW, what ever happened with you're whale shots?
Please let me know what you decide.
Mark.

Get the 20D, It will improve you're odds of getting a saleable photo, It has a magneseium body (You know you want it!) And promise youreself you will sell 100 prints @ $5.00 profit, Or 10 prints @ $50.00 profit.
Ok, seriously and honestly, I think that upgrading the rebel is a poor cheap option, buying a 10D is a waste, but getting the 20D just makes sense!
BTW, what ever happened with you're whale shots?
Please let me know what you decide.
Mark.

I guess I will just have to sell a few more shots...

No one ever bought my whale shots. But, my ecology professor did decide to incorporate them into his slide lecture on aquatic mammals. By the way, a week ago I got some more! What are the chances of that?

Ryguy, ok, heres another thought, work w/the rebel and get the edu under youre belt first.There's no big diff btwn 6 &8 MP slr's as far as image quality. At this point in youre life I dont think an upgrade to the 20D warrants a $1200 dollar investment just for faster frame rate, but if you can work it in...
I am sorry to hear that youre photos did not sell! You already own the copyright to them, but you should pay the money to get documentation on them. if anybody does use them it will make it easier for you to be compensated
I love the last whale pic! great shot! Did you get youre lens fixed?
SHOOT WITH WHAT YOU HAVE. An addage Iv'e read.
Mark.

Nope, I didnt get my lens fixed. It still feels a little loose. I still use it and it took the picture of the whale I just posted. It would take 2-4 weeks to fix and I didnt want to do it at the moment.

But anyway, I could probably sell my rebel for 400-500, so a 10D is only about 300 more than that, and I could afford that much. If I can find someone I know that is selling theirs I might go for it. I am wondering is if the 20D is that much better than the 10D. In particular I am wondering about the autofocus, noise, and white balance as compared to the 10D.

-Ryon

The reason I say getting the 10D is a waste is that I dont think its that much better than the rebel.
I am not all that familliar with these things. Look at post #6 from EOS3 "stay away from the 10D".
I know you want somthing better, just try to use good judgement!
If I had my way, I'd have an $8000 16MP cannon instead of my D70. But it works.
Mark.