(sort of lengthy)
Hank-
Considering that Intel is going to drop prices on that processor as well as the much faster E8400 (3.0GHz) in July or thereabouts, you might want to hold off a bit since the overall price of a system should reflect the savings. The Optiplex has been a good staple for Dell in the past but unless you are buying one of their very high-end gaming PCs, that system is pretty much status quo-- even less IMHO. That 256MB video card they offer isn't anything special, the same for the 250GB HD. For future headroom you really should have nothing less than 512MB onboard vidro RAM. The 4 gigs of 800MHz RAM will likely run at 400MHz and with Win-XP you'll see a reality of about 3.5GB out of the 4 unless it's a 64-bit OS. I don't know what your needs or specific uses would be for a new 'puter, but for me I wanted something that could run the normal gambit of software, yet perform admirably for gaming.
The problems with most Dells, Gateways, HPs ect. is the BIOS is very limited for user settings. I have an old Optiplex, circa 2002 and it's constructed to last for many years as compared to present day Dells where cutting corners is quite obvious. I'll never go back to buying a ready-made system from a company since they often bundle crap software with it, and the mobos are on the limited, weak side for user flexibility.
If you have some computer savvy, perhaps you can create a custom build from sites like Tiger Direct, CyberPower PC, or NewEgg. I recently bought a tower only, which houses a E8400 3.0G Core 2, 320GB SATA drive, media card reader, floppy reader, Lightscribe DVD burner, 600watt dual rail PSU, nVidia 8600GT GPU with 1gig RAM, 4 GB of Corsair PC6400 RAM, custom gaming case with fan control, temp. meter. volume meter, 3 heat pipe copper CPU cooler, and an ASUS SLI mobo --- all for about $700.00 and I can safely overclock everything inside this case!
Since Circuit City is about to close their doors they have been placing many items on clearance so I got me a gamer's back-lit keyboard, wireless 5-button mouse, and a second DVD burner all for well under $100.00
Now I must admit that going it alone in piecing together a PC can have its downsides. Right now I get occasional system lockups, but I'm narrowing it down to RAM latency settings and I'm hopeful that once I dial in the right numbers, and sync the memory with the CPU, system instability will be a thing of the past. A small price to pay initially, for performance that's way beyond practically anything Dell offers and for much less money too.
Just last night I started building a second PC for me to use as a basic server and software test-bed. Someone discarded a nice mid-tower, complete with VIA mobo/ Pent IV @ 2.oGHz. Add in a 450w PSU, ATI 1650PRO GPU, 1.5 gig DDR RAM, two DVD drives, media card reader, floppy drive, USB expansion card, 2 HDDs, custom cooling efforts on my part and I'll have a 'puter for an investment of well under $100.00!!! And the mobo and RAM can be overclocked with ease.