What do you want to do with your new computer?
I'm a pentium fan.
The E6600 is easily overclockable.
It uses less power vs AMD and is a great processor for windows applications. I have the E6400 and I love it!. I'm a pentium fan btw.
Regarding the DDR2 800MHz ram. Your Pentium E6600 will have a Front side bus of 266 x 4 = 1066MHz.
Your memory will be 400x 2 = 800MHz. If you run qty: 2 1GB Memory Sticks in Dual Channel, you will effectively have 1600MHz. Over kill for your stock speed FSB of 1066MHz. So you really only need to buy DDR2 533MHz in dual channel will give you the 1066MHz. If you want to go higher, I'd recommend DDR2 667MHz. This will allow you to save 50-100 dollars that you can use to buy low latency DDR 667MHz Mem Sticks.
If you plan on overclocking, then I would get the DDR2 800MHz sticks. I did.
seagate now owns Maxtor, just to let you know. Sata II is cool, but make sure the rated speeds are 3.0g/s or faster and also compare seek times along with size of cache on the Harddrive. 16Mb is better than 8Mb. Seek times and cache size are more important than capable transfer speeds from HD to motherboard via sata II. Just because it's SATA II doesn't mean it will go 3.0g/s. Actual transfer speeds may not always be 3.0g/s due to seek times slow and fragmented files. Basically, if the file is larger than the cache, it most likely will not transer at full 3.0g/s speeds. I still got sata 3.0g/s hd because I wanted it, but my seek time is 9.3ms and I hear that is slow.
Cool PSU. I look for reliability and efficieny in PSU. I'm only a ANTEC PSU fan. I've only bought antec power supplies so I may not be much help.
Cool video card!
Cool monitor. I hear that is a good one.
I don't know anything about that motherboard, then again, I don't know any other motherboards except my own. I stick with ASUS motherboard due to their chipsets, and usb, pci slots, pci-e 16x and other features.