This is the place to rave about my Boss ME-70, the replacement for the ME-50. It's brilliant for me. Most of the time I'm super happy just to plug in directly, but it's nice to get some reverb once in a while, a compressor or a clean boost on a footswitch are good to have, and a parametric EQ. Once in a while I'll use delay, tremolo or chorus. And it's got a looper which has been a great practice tool. And a wha just for when you're in the mood. And you can plug in your ipod and jam along, into the amp or with headphones, and it does decent modeling of a few good amps (better than the pod stuff and better than a crappy SS amp) so I can go direct into the PA at practice for convenience, and use the volume pedal there while I'm at it. Basically I'm not an effects guy so it's fantastic to have all this if and when I want it, without spending a bunch of time and energy on pedal stuff or learning to program one of the 'big boys'.
Oh, and there's a bunch of other weird stuff like Leslie Emulation and auto-wah of course, and everything can be controlled by just the knobs, no programming necessary, and it's one nice solid chunk of metal. Love it love it.