I tried the VOX a Line6 BassPod and a couple others, then I plugged into my Mac with a $3 1/4" to 1/8" adapter and fired up GarageBand. The Mac gives me way better sounds and I get a bunch of effects and amp simulation.
I travel for work a ton and I simply pack a bass and a pair of headphones, my laptop is always there. I can practice all I need to in hotel rooms without bothering anyone. Works fine at home with the kids sleeping too.
They make PC software that does the same thing as well. Obivously you have a computer or you wouldn't be on talkbass.
Oh and you can record right into GarageBand, and you have MP3s right at your fingertips and there is a bunch of "slowdown" software out there so you don't need any of those goofy gadgets. I would almost contemplate building a laptop into a rig now-a-days.