Hello fernandes...
Here is my personal opinion about Your questions and everything...
1. Dont bother with buying PCI-e motherboard...they might promote it as best of the best...but its not like that...just look at some graphic card tests...You would soon realise that PCI-e versions arent more than some 5% faster than AGP (if at all! - because some are actually slower)...I just wonder if that was good move to go that fast from AGP to PCI-e, because AGP8x wasnt even pushed to its limits - I am sure there were still plenty of free space for some improvements...
... Also performance/price ratio for PCI-e products is way too high at the moment...at least wait few months until prices drop a bit...and also until all this chaos about them settles down...
2. You said You wanna buy some cheap version of extreme cards...well...6600GT AGP sure is good buy at the moment...but dont know which X card from Radeon did You have in mind? 9800Xt? X800? X800XT? X850?
Well...6600Gt sure is better than any 9800 card...no doubt in that...but for others...You would need to do some "deeper comparation" of them...
I have included a link
HERE to one of many comparation charts (this one is of PCI-e cards...but on the left side of the page You could find VGA CHARTS 4 which includes AGP cards charts...), so be my guest and check it out...
And finally...best wishes with picking Your next graphics card...and let us know which one You choose...also...if You have any more questions or anything...also ask...we will gladly help...
ENJOY!
*SILICON-OUT*