D90, 40D or new lens for Rebel XT?

Hi, I face a tough decision and need some help from the pros out there. I currently have a Canon Rebel XT with a Tamron zoom lens. Now I have some money to spend on an upgrade. Because we are going on a 2 week vacation in September, I was initially thinking about buying a wide angle lens for my Rebel so I could take some better landscape pictures and get some variety.

Now however, I also have the opportunity to get my hands on a 40D quite cheaply and I was also looking at the Nikon D90 which seems quite impressive especially with the video capability and all. I could however only get one (probably kit lens) with the D90 and could not afford a wide angle right away. Still, the D90 seems great but I am not sure if I could still get a good price for my Rebel with zoom lens to cover some of the switching cost?

So what would you go with? D90, 40D or simply a nice wide angle lens for Rebel XT and upgrade to a new Canon body sometimes later? I hear the camera body is not as important as the lenses but I imagine the picture quality from a Rebel XT to a 40D or D90 should be quite a difference per se, right?

Please help! Any opinions are appreciated!

Thanks

I'd go D90 but I admit to being a prejudiced Nikon owner with 5 lenses.
If you had several lenses I'd say to stay with Canon by either upgrading your lens supply or getting the 40D to go with the lenses you have.
Which Tamron do you have? Are you getting good pics with your xt?
I'm sure someone with more knowledge than I will jump it but in the meanwhile WELCOME to the Forums and hang around and share what you do!

Hi slang 21.
I just traded in my Nikon d40x for a Nikon d5000. Check it out. It's between the d60 and the d90. Getting the d5000 might also leave you enough dough to buy a nice Nikon lense.

We always want new cameras. Digital SLRs and all their fancy new features and specs get all the attention. But it's rare that a new camera can really offer you a new way to be creative. A new lens almost always offers new ways to express yourself and solve problems. Lenses also last. I've had my Canon 70-200 f/2.8L for about 12 years. I don't even know how many cameras I've gone through in that time.

So yeah - get a new lens. Sure, a new camera would give you some more speed and better low light image quality. But a new lens will let you see and shoot things in new ways. A new lens will really help you grow as a photographer. You can always buy a new camera later. But the lens will make a big difference as soon as you slap it on your camera.

In my honest opinion Stick with the Canon Xt, and Upgrade lenses.
if you do get a new body, will you know how everything works in time, will you be comfortable in time to take good pictures?