I tend to create my own loops, just build somethigng up in the sequencer and tweek it until it sounds right.

I download samples from the net, percussion stuff and synths and then just tweak
them until I hear something I like.

I use sounforge 7 to chop up loops i have downloaded sometimes as well.

i tend to use soundforge 7 to master completed tracks, make sure my EQ's
are perfect e.t.c.