CPU: even as an AMD fan, I can say from reading about if you're going intel, and plan to OC someday, the Q6600 is a winner.
LOVE THIS RAM. Will be getting another 2 sticks soon.
MOBO: Intel fans can help you better than I, but Intel boards don't seem to be the way to go, and I have an Asus borad, and they are good quality. I also had to deal with them for an RMA and it wasn't a bad experience, although not perfect.
GPU: Only go with that 2600 if you are on the tightest budget. You said you want somethingthat will last you the longest? Try this.
This might be slightly outside your budget, but it is plenty for what you may need in the next few years and will OC like a dream. (see my sig)
Tower: Smart move. The Antec 900 is awesome, and considering you'll probably get a newer model with holes predrilled for cable routing, it'll be nice to have. I love mine. Only thingis plan on cleaning it every 4-6 months because it's a stinking lint trap.
All other pieces: do your research, listen to others, and good luck.