I'm currently looking at two CPU's. The Q6600 and Q9550. I'm debating the two. I don't plan on overclocking. I hardly see any reviews or info on the q9550 which is why I am thinking of staying away from it.
you need to look at hardware from the viewpoint of what you want it to do for you,and what you expect to get out of it in terms of performance and long term sustainability,and sustainability varies for each of us...
Q6600 is a 65nm process which means that it will use more voltage and produce more heat than the Q9550 which is a 45nm process. If you don't plan on overclocking, the Q9550 will be better for you because of the higher clock speed. I can see the difference in games from having lower clock speeds. In DODS with my Q6600 at stock 2.4 ghz, i get an average of 50 fps. But when I overclocked it to 3.0 ghz, my fps jumped to 80+ depending on the map. It depends on what you're going to do with the processor but for games, the higher the clock speed, the better.
Edit : I ask this because I've worked with those programs also and if you have the money and you really want to a see a difference go with a dual processor setup. Or wait for i7, I'm not sure, but I think that should bring significant gains to programs like these. Especially with Intel bringing back HT. All I can is, it's about time.
I have a dual core 45 nm and used to have a dual prescott xeon setup. Although the 45 nm is faster, the dual processor gave a better multitasking feel overall. The difference in speed is obvious why the dual core was faster up front. The 45 nm core duo has better arch, but that's not the point. Your looking for a smooth multitasking feel which only dual processor setups can offer.