I've got an i7 920 and it's great. A couple of thoughts:

The RAM modules you've selected are a bit wasted as the i7 only supports 1066 modules (unless you overclock). At any rate they're of great quality, plus I'm not sure if you would save any real money with slower modules.

I would buy a fast hard disk, as I guess the stock unit from Dell is pretty much terrible, otherwise your CPU will be constantly waiting for data from the hard disk, especially when working with large solutions in Visual Studio. WD Velociraptors come to mind (2x in RAID0 is awesome, trust me).

I second buying a new hard drive, but go for an Intel X25 solid state disk. They're still a bit expensive, but buy a small one as system drive and keep your existing one as a data drive.

Also, if you buy six memory modules instead of 3, you may turn off the Windows pagefile or put it on a RAM disk.

Yeah, I'm not convinced that SSD's have quite gotten to a price point I'm comfortable with, but I'm sure I'll go there at some point.  Regarding HDD's in general, though, one thing I'd really recommend if you're not already doing this is mirroring your HDD's.  They're cheap, and the insurance factor is really nice.  My home machine has a pair of 1TB 7200 RPM drives, and at some point, I hope to add the aforementioned SSD for a boot drive and a pair of lower-RPM 2TB drives if I need more data space.

If you do end up running multiple drives, I'd consider looking at a case that's got support for 5-6 drives with a place to mount fans specifically for the drives -- IME, these can run pretty hot, and cooling seems to keep them healthy longer.  I've got an Antec Sonota case now, which is decent, but if were to buy a new case, this one would be high on my list:

www.newegg.com/.../Product.aspx

Finally, the 450W power supply with that case is probably ok w/ the equipment list you've got here, but if you would end up w/ multiple HDD's and a hungry video card, you could be pushing that a bit.  Thermaltake is a good PS, but if you purchased a separate case & PS, you'd also be able to get an 80+-rated PS, which should end up just a bit more efficient.

Good luck w/ the build -- looks like fun.

I would try to look for a cheaper processor and motherboard, and then put in an SSD :)

Good luck with the build!

Sounds like a nice machine - I would also recommend upgrading to 1 or 2 WD Velociraptors as that's the main bottle neck.

It might also be worth getting 4 gigs of RAM instead of 2 as that seams pretty standard these days.

Might want to check out some testing I did with various configurations before purchasing your own.

http://rsurl.net/blog14

I would first suggest a better power supply, especially depending on your video card and the number of HDDs you plan on running.  you might want to consider a core i5, you'll save about $250-300 with maybe a 15-20% cpu perf hit (1/2 the cost for 85% of the speed.  With that do a decent 64-80GB SSD for booting/os and a decent 7200 rpm HDD for mass storage, which will more than make up the difference in CPU performance for your usage.  A Phenom2 265 may be worth considering as well, unless you plan on dropping another $500+ for a faster CPU in the next 2 years, the 1366 boards imho arent really worth it.

I think , this should be your main HDD as well ,

its a 40gb SSD

www.newegg.com/.../Product.aspx