Dell forum: Inspiron vs Dimension desktop?

I have NOT purchased a Dell computer in over 5 years. My current one is a Dell Dimension 8300. Dell always has some coupons, sales, and promotions. Currently, they have a trade-in offer I'm considering.

I've done some searching and it appears their product lines have shifted yet again, with Inspiron desktops more or less representing Dell's lower end of the desktop lines while Dimensions the higher line of desktops, but also having branched out to business consumers as well.

I'll need to read up on how components have changed since then (processors, types of RAM, which video card to spring for to suit my needs). However, as a home consumer, I'm wondering just which model line I should be getting, Inspiron or Dimension. While I'm sure I couldn't go wrong with either of 'em, I'd like to get it right before I make my purchase, as this machine will likely last me 5+ years as well, and some types of hardware modifications will be too unwieldly for me. Among my uses include....

MORE HIGHER END:
--some programming and development, such as with Java or C++
--Basic image editting (nothing fancy like layering with PhotoShop, but stuff like cropping and size manipulations)
--higher end PC games such as Halo 2, BioShock, and whenver Starcraft 2 comes out.

MORE BASIC:
--multimedia (viewing/listening to music, pictures, DVDs, and other video clips)
--M$ Office (the typical, Word, Excel, and some Powerpoint, Access, and Visio)
--web surfing
--burning optical discs



Some advice on which model line, and any concerning specs I should be looking for will be greatly appreciated!