external hd question

[turnipmonster]

hi everyone,
I want to get a ~150GB (7200 RPM) external drive for recording music. questions:

1) where's the best place to get the best deal?
2) firewire or usb? I have ports for both.
3) any brands I should look for or stay away from?
4) are most ext drives bus powered or will I have a choice? if I have a choice, should I go with external power? I don't want to overload my laptops power supply.

thanks for your help. I don't buy hardware often and really don't keep up with this stuff.