Do I regret it? A little.
First of all, all these websites and people saying that the 4850 "blows" the 8800GT out of the water... is just not true for me. While I don't deny that the 4850 is not faster, but it turns out that the increase isn't enough to make a difference for my gaming at 1600x1200. If my games @ 1600x1200 struggled with fps under the 8800GT, then they also struggle under the 4850. So in my scenario, the 4850 did not make a big impact. Now if you're gaming at a lower resolution, and the 8800GT was barely struggle but struggle, then perhaps the 4850 would make a difference!
Secondly, the heat issue. I won't spend time to discuss this as it has been discussed in here in every other thread.
Thirdly, driver stability issue. This is perhaps my biggest beef against the 4850. I was humming along fine under XP and 8800GT, games are all rocking. But with the 4850, I paid for "improved" hardware but am sitting idle because my games are not stable. And as a side effect, I've spent a load of hours trying to unsuccessfully fix all the crashes, reload drivers, and finally, in a desparate attempt, dumped XP and put on Vista.
And a month after the 4850 release, there is still no official Cat 8.7 release. Because of this, I feel that AMD was using me as a beta tester, and I'm insulted by this. I understand if AMD took 2 weeks to release drivers for a new hardware, but a month?? Unacceptable.
All these have definitely left a little bitter taste in my mouth. Next time, I will definitely think twice about buying AMD again, and I would only buy AMD if I see their new drivers release with the hardware, or buy the hardware at a huge discount. I bought the Visiontek 4850 for $150 at BB a while back, so I feel a little bit fortunate in that i'm not paying $170 for it while playing the rebate game. I feel sorry for those guys who "pre-ordered" the 4850 for $195 on fxvideocards.com though!
What I should have done was to get 2 Zotac 8800GTS G92 on Fxvideocards for $119/ea AR and Sli them together. For $240, that would have been the damn best bang for the bucks! But I bought into the 4850 hype. Oh well.