The Geforce 7300GT fully supports OpenGL 2.0, so the framebuffer support is no problem at all. Performance-wise, it should be 100% fine if you are just intending to use it for N64 emulation (I'm not totally sure about actual video game performance, like with BF2, Oblivion etc.)
EDIT: As gokuss4, a Geforce 6600 should be fine. I use a Geforce 6600GT for all my coding and testing with the glide wrapper, and it is perfectly adequate for N64 emulation.
Are you saying the 6600 is better than the 7300 GT?
The funny thing is I've been quoted $235 for a GF 6600 25MB which is an utter rip off, that is why I thought the 7300 GT sounded such a good bargain for $150. Also there were some positive reviews for the 7300 GT which said it was alot better than lower end Nvidia cards which I assume the 6600 falls in.
I would have prefered to go higher and get the 7600 GT but sadly they're atleast $420 - yes it's ridiculous!
And I won't use eBay, even though it may be cheaper cos:
1. I don't have an account.
2. I want the card now, not next week (Though I might have to) ...next month.
3. I don't trust paying someone I don't know for something I haven't seen or got yet.
4. And who says it will be cheaper after you've bid for it? You may come out twenty bucks cheaper and be disapointed with the quality of the product.
Anyway, I guess I'll have to still look around before I make a decision and every day it's getting harder to find an AGP card for a realistic price which really sucks cos I only had my computer for 2 years and everything now is changing.