For LN2 Kingpin uses the super cheap paste's from Microcenter. So if you doing sub zero, anything ceramique based should do.
Use MX-2 Nate, its a lot cheaper and performs within a degree of MX-3 if I remember correctly, but I know its close. OCZ Freeze is another one that is fairly cheap with good performance.
Forgot to mention. IC7 is a B*TCH to get off heatsinks\CPU's, and there noticeably "duller" looking after you scrub for 5 minutes to get that crap off.