Hey there, Dennis.
From what I can see about this model, you can get an mSATA SSD with a capacity of up to 512GB. Of course, I'd always suggest the larger one if possible, as you can never have too much storage space, but that depends on your budget as well. A 256GB mSATA SSD would have more than enough space for your OS, program files and probably a couple of games. As for a specific drive, sorry, but as a Western Digital rep, I can't really recommend a specific brand, but I'm sure that the guys from the community would be more than glad to offer some help.
Cheers!
Boogieman_WD