There's a lot of options, if you don't won't to carry around the MPC1k and a laptop. I only no the the MAC stuff, so here goes:
>Bitshift's iDrum - 16 step seq. (promise of more steps soon), so freakin' easy to use, loads wav and aiff, 99 paterns, with as many tracks as you computer can handle (which should be a lot if they are drums), automap midi option (takes me 10 seconds to load all my samples and map them), had loads of promising features and is only version 1.0. i'm using it now with the mpc. it's no replacement but a very viable option.
>Akai's MPD16 - great midi controller, just choose your software and go!
>There's loads of controllers out there....there's also software that'll turn your keyboard into a virtual midi controller, so you can play your keys or samples like pads! (check
http://homepage.mac.com/seishu/ssworks/MpcPgmMaker.html go to MicroSynth and see)
There's always Reason to, i can't stand the generic sounds and feel of that program but people like it and it gets thumbs up on the low CPU usuage. Reaktor is a very serious option that get's overlooked by hiphop heads because of how it's marketed at Dance, Trance, Techno and the IDM folks, it's amazing....synths, slicers, grinders, pads, sequencer's, live tools, create you own synth or what the hell download one of the 3,000 plus synths others have made on NI site. Go to Native-Instruments.com, look for community, go to user library's, check out all of the free synths, sample tools and fx. (i dig it but this program isn't necessary if your just a loop digger....)
The MPC1k is small and takes up little space. It's seq. is rock solid and it's features are really amazing, given it's price. There are other options but i wouldn't buy any groove boxes or whatever. Get the MPC1k (any MPC, for that matter) or go software, or both in my case. Check out Prefuse 73 to here how far programing on the MPC can go.