Multi-effects processor advice?

[The Lowe Down]

I am looking for a multi-effects processor, preferably rackmount for my rig. I am mostly looking for Chorus, Overdrive, and Delay tools for shaping my sound. Mostly for home and recording use, but probably light gigging too. I am not keen on a huge pedal board, so my thoughts turn to the multi-effects devices out there. (My head is rackable, so a rackable unit appeals to me for transport.) I would like to stay under $500 and I am not against used gear, but the budget is a little flexible if I can justify the difference.

I have spent a little time with the Line6 bass pod and their XT line, but not enough to know that is the right option. They also have a new X3 line that I haven't touched. I am just looking for the good, bad, and ugly of the units out there right now and if there are certain ones to run from. Firsthand experience trumps good marketing any day.

I don't have a certain "sound" I am looking for specifically, I like my current GK sound and tone I get out of my basses, but I do like my fretless with a good chorus, and overdrive does some interesting things with my the Barts on my 5 string. I play primarily blues, R&B and jazz, but I want to be able to cover some metal and heavier rock. It is harder to cover the later without some grit in there.

I am also a very saavy computer user, it is my day job and pays for the toys. Any integration to Mac or PC is highly preferable. I know many of these units can be upgraded and programed. Most of my adventures with my tone have been through a couple sequencers on my Macbook and I like what I can do there. I don't want to be dependent on my laptop in a gig, nor do I want to have to bring it along.

Any help is well appreciated. TIA