Well... I never had AMD's... when I had no knowlede about computers(Year 1999), I bought a PIII 550Mhz with a crapy mobo, integrated video and audio, 128Mb RAM and 20Gb of HD....
then... when I figured out that I begun to love computers....(Year 2002) I bought a p4 2.53Ghz, 100Gb HD, 640Mb RAM, All-In wonder ATI Radon 8500 64Mb, integrated audio, and an Intel Mobo... then I upgraded this computer with a Powercolor Radeon 9200 SE 128Mb
then, I figured out that ATI is not what I expected, even when I defended it a lot in fornt of my nVidia friends... and Pentium series from Intel... is really crappy... So... I decided to switch to nVidia.. but I didn't want to leave intel.. so I gave them another opportunity... Soooo......
on 2004 I bought a Supermicro X6DAL-TG mobo, 2 Xeon Noconas 3.2Ghz EMT64, 2Gb RAM, 160Gb HD, Gigabyte 6600GT, and everything watercooled with a nice Koolance PS2 case... The video card was pretty good, it runned Doom 3 with no lag on high resolutions and details... but for 3D modeling it wasn't powerfull enough... Soooo....
2 weeks ago.. I updated my computer... I bought the latest supermicro mobo SLI capable, 2 BFG 7800GTX SLI config... 2 more Gb of RAM... so right now I'm working on a 2xXeon Noconas 3.2Ghz, 4Gb RAM, 2xBFG 7800GTX OC, 160Gb HD.... same koolance case (by the way.. the mobo is big as hell... I had to move the water pump from it's place in oredr to fit the mobo)... mmm... I didn't notice enough performance increase as I was expecting...
right now, I'm planning to leave Intel and go with AMD Opteron... So My next computer will definitelly include 4 Opterons (Dual core ovbioulsy), a pair of Quadros FX4500 or the latest ones... something like 16 Gb of RAM.... and a Tb of HD I think...
So after a lot of mistakes with video cards and CPU companies.. I found out that AMD is the best on CPU's... nVidia is the best on Video Cards... that's it.... no matter what Radeon people say... no matter ATI releases it's R520 with their copy of the SLI tech (I can't remember the name)... Nvidia will allways be the best... I was ATI guy.. now I'm nVidia... I was Intel... now I'm AMD...
take my advice