In my opinion, Cubase SX2.01 or Nuendo2 are the best. Nuendo contains everythign that SX2 + more advanced features related to post productions.

It really depends on your budget. But the best two cards I would recommend are:

RME: best compatibility with Cubase
or
Lynx: the best convertors in its class

The above are the best no question asked. If you go to the professional Nuendo, they strongly recommend them above everything.

USB is good for midi interfaces. Some were recommending Steinberg Midex 8