I want to buy a Midi controller for Garageband.

1. Do I need to buy a midi interface or can the keyboard plug straight into the comptuer via usb or firewire?

2. Is there going to be latency issues?

3. Do I have to buy an external sound module or can I use the garageband virtual instruments?

3. Please recommend a 25 key midi controller for abut $300
1) most current midi controller keyboards will have a usb line.
2) possibly, depends on the comp and software
3) You can use the virtual instruments. also can add hardware or other virtual instruments
4) Axiom are decent. you could also look at the xio synth by novation.