Just about anything that's currently offered will do what you're looking for, but I'd stay away from the Minis and iBooks if at all possible. I was doing far more intensive projects than what you described on a G3 iBook up until a month or so ago, without any issues (some lag, but nothing too bad)there's still a lot of designs shops using G4 (400MHz and 500MHZ) era models.
- Any (dual-core) G5 model with 1GB of RAM & a 20 or 23 inch Apple LCD (the 30" one is a great item, but pricey and not required...two 20's or 23s are a good alternative/bang for the buck in its place). 2GB can be had for very little $$$, so if possible go for it.
- 15" PowerBook with a minimum of 1GB of RAM (you can upgrade to 2GB [2x 1GB] from OWC/Macsales for less than the price of 1GB [2 x 512] from Apple [remember, the PB only has 2 slots]). On a PB, I'd definitely try to max it out (I currently have this model with 512MB...it's usable, but definitely will need more RAM in the future).
LCDs are the choice today and in the future. Apple's current offerings are more than capable and usable for design work, not to mention they are priced well.
LaCie offers LCD models (they no longer make CRTs), some of which equal or beat (price & specs) those offered by Apple. It really depends on the budget and how important color matching is to you. It's entirely possible to use Apple's display and get good output, it just might take a bit more initial setup than if you used a 2-3X more expensive LaCie model with BlueEye.