I've got an old (relatively!) Roland VS-1680, which is a bit out of date in terms of having basically zero capacity to interface with a laptop/desktop computer (a problem solved in more recent VS models), but otherwise is well equipped as a "studio in a box", with a good range of inputs and effects/amp sims. It is, alas, a little difficult to use as a solo artist unless you've got it set up with all your other kit plugged-in -- something which is hard for me to manage in my currently limited living space! The iBook/GarageBand setup, with onboard software drum machine/drum loops + cheapo MIDI keyboard + USB audio interface is more compact and faster to get into action (plug in and go!), so that's working for me at the moment.
Ideally, I'm eventually gonna have a place to live with a dedicated studio space -- nothing fancy, but with everything set up a ready all the time. That'll be cool. I might get a mini-tube amp in there some day, but it'll be amp-sims for the forseeable still. But there's no reason I couldn't have a couple of different amp-sim solutions to choose from! :)