Buying a new Dell desktop - need input

[MediaPA]

Ok, here's the system that I speced out. It's going to be just under $2,200. I'm interested in finding out if there is anything that I can do to make it last me longer. I want to try and get 4 years out of this computer. I like the occassional computer game, so hopefully this will be current enough for gaming for a few years. Any advice or is this overkill for a personal use system? Does the price seem good?

Also does anyone know the difference between the 8400 and XPS? With the same hardware, the XPS was $500 more.

Dimension 8400
Pentium® 4 Processor 550 with HT Technology (3.40GHz, 800 FSB)
Microsoft® Windows® XP Home Edition
2GB Dual Channel DDR2 SDRAM at 533MHz (2x1GB)
20.1 in 2001FP Dell Ultrasharp™ Digital Flat Panel
256MB PCI Express™ x16 (DVI/VGA/TV-out) ATI Radeon™ X800 XT
250GB Serial ATA Hard Drive (7200RPM)
16x DVD
16x DVD+/-RW w/dbl layer write
Sound Blaster Audigy™2 ZS (D) Card w/Dolby 5.1
Dell 5650 5.1 Surround Sound Speaker System with Subwoofer

Microsoft Office Basic - Includes Outlook, Word, Excel
McAfee SecurityCenter with VirusScan, Firewall, Spyware Removal, 15-months
1Yr Ltd Warranty, 1Yr At-Home Service, and 1Yr Technical Support
CompleteCare Accidental Damage Service to 1Yr Lim Warranty