Uhh, you got your info backwards man. The 8600GTS loses to the X1950Pro in almost everything, the X1950XT pretty much wipes the floor with it.
There isn't really any contest between these cards, get the X1950XT. The 8600GTS won't be able to run games in DX10 appreciably anyways (hell, an 8800Ultra has trouble running games like Call of Juarez and Lost Planet in DX10).
cool, I actually bought the X1950XT, but then saw the other card and noticed that it had faster clock speeds, etc. I still don't know how to read those specs..
Yikes! Clock speed isn't a good way of comparing cards when you're talking about entirely different GPUs. I'm pretty sure there is an Nvidia 7300 that is clocked higher than my 7800 GTX... that clock speed difference means NOTHING (well, practically nothing) because my card is utilizing 24 pixel pipes against the 7300's 4.
So here's the road analogy... clock speed is how fast the cars are traveling... other factors (such as the number of pixel pipes/stream processors, memory bandwidth) determine how wide the road is... overall performance is how many cars are able to travel at once. You can have a really narrow road with fast moving cars and still not be at a performance level you want.
It is hard to convince yourself that the older card is the faster card. If I were in the market for a high-end laptop right now, I'd have a hell of a time forcing myself to buy one with a 7950GTX... numbers tell me that is the fastest mobile GPU out presently, but in the back of my mind it'd bug the hell out of me that it didn't support DX10. I imagine the OP was going through something similar in his mind.
And you're right... thankfully he made the right choice. Anyone who buys an 8600 over that 1950 had better have a very specific reason for that purchase or else they're going to feel like a horse's ass once they realize what they've got.