Another vote for the Antec 1030. I say get it in the black version. It's also available with an Antec 400 watt power supply, ATX 2.03 compliant. That's what I got. (That power supply is both Athlon and Pentium 4 (think two years from now, maybe) compliant. P4 is tough on power supplies.) The 300W antec that comes standard is also Athlon approved. (It might be 2.03 P4 compliant, don't know.)
The black 1030b is really a beauty. Size is between standard midtower and tower, closer to midtower. 4 x 5.25 bays, 2 external 3.5's, and 3 internal 3's (or 4 if don't use the second external). Comes with 2 fans out the back, nice pop in holders for two more 80mm sucking in from the front, including one over the internal HDD bay holder. Nifty.
Room in there for a dual processor mobo. Can take any mobo, actually.
Super case. I plan on keeping mine for about 10 years!