I assume you're looking at playing with others including a drummer? For that, and assuming your drummer has an acoustic kit, I think you need an amp rated at at least 200W to give you some headroom; you might get by with 100W but it probably won't sound good if you have to push it and that could damage the speakers. If you like Ampeg the Rocket Bass 115 would be worth a look, or the Fender Rumble 200, Trace Elliot Elf combo, Ashdown Studio 210, etc. Most of these will give you about 130W with no extension cabinet, which would be good for rehearsals, but could be expanded to 200W or more with another cabinet when you're ready to gig.