One of the best bang for the buck filters I've seen is from Marumi. There was an article a few years back looking at a bunch that did some pretty serious testing and I have to assume the quality has not slipped since then. The competition may have improved, but..... They can be found on eBay for around $110 for 77mm, and I think there are some other direct sales sites for them as well. Quality compared to B&W...

Polarizing filters test - Introduction - Lenstip.com

The latest Hoya Pro1 and HD filters should be better than the ones reviewed in that article, based on everything I've read about them. Lower light loss, etc...

But, I'd try to stay away from the cheaper basic single coated filters out there. I've had bad results from basic Tiffen and the single coated Promasters in the past. Those were before I new any better. For a lower price than the multi-coated Promaster you can get the Marumi Super, which is thinner, sharper, more consistent, and basically better all around....

Anyway, have fun shooting!

And yes, buy a 77mm, and step down rings for any other lenses you use... That is, unless you have a smaller lens that really needs the hood for how you use it... Then, well, gotta drop more $...