If you want to record drums and also jam sessions, you may find two inputs restricting. To mic up drums successfully you may nbeed to use a couple of mics. Also you can get some nice effects by using a DI for an accoustic guitar and also mic at the same time. This way you can blend the sounds to get some different tones and add some depth. If you are jamming with a friend then you would deffinately want more than two inputs. Probably 2 mics, and a couple of DI's for the instruments. Also you may want to plan for more expansive requirements in the near future. No need to buy equipment twice, thats a costly exersize.
For all of the above reasons I recommend more than two iputs with your device.
Another thing to consider is latency. The best way to combat this si to ensure that you have fast communication between your hardware and your pc. Especially when recording multiple streams and using plugins or VST i's. The fastest is USB2 very closely followed by firewire, USB1 is outdated technology and should be avoided ( apologies to those who still use USB1 hardware )
My personal set up is with an Alesis Multimix8 USB2.0 it provides me with 8 inputs ( 4 stereo and 4 mono), mic phantom power on 4 of the inpouts, built in effects, eq on every channel, send and receive on all channels, main out, control room out, line out, headphones out. It is flawless and acts as a good mixer as well as soundcard. I can take it and gig with it.
I am sure there are many such beasts out there that would be as good as this one, but I hope this gives you some idea of what to look for.