Yeah with the +drive you can store lots of samples on it.
If you go for the MD without the drive you will definitely want to upgrade it, maybe not straight away but best if you can get one with it already fitted rather than having to send it to sweden to get it done
I can say that I NEVER get bored of my MD. Between the P-Locks and the LFO's the possibilities are endless for twisting the original sounds you start with.
But even without all that I just love making grooves on this thing! It's a joy to use
It lets me get out of the studio and away from the computer, take it in the living room with the headphones and just make a bunch of sounds/grooves.
Building drum kits is a piece of piss.. choose some drums either from the on board 'Machines' or samples or a combination of both. Lay down a pattern then save it as a kit. Then start twisting it all up until it sounds completely different to what you started with and save that as a new kit. Repeat this a few times and suddenly you have lots of new kits to play with.
The sequncer is rock solid. The swing is quite good but sometimes it can be hard to get things sounding loose on it (for hip hop or whatever). You can get round this though by using the LFO's to delay the start times etc. The LFO'S can do all sorts of stuff that I havn't even got into yet