Left/Right Arrows=Previous and Next Marker (custom, I think...)
< & > ( technically , and .) = Go To Start of Measure and End of Measure (custom)
Ctr+Left or Right Arrow: quick horizontal zoom in and out
F3-Bounce to Clip (custom)
F4- Apply Trimming (custom)
F5- Lock Clip Position and Data (custom)
~ - Select None (custom)
U= Restore View To Previous State (custom)
G= Center View on Now Time (custom)
Home= resizes and zooms tracks to see entire project (custom, super useful)
Mousewheel Press= Tool Hub
W=Return To Zero
K=Mute
B= Browser
I= Inspector
D= Show MultiDock
Z= Zoom Tool
Ctr+M= Melodyne Region ( for lots of vocal editing, this is really helpful)
Oh, and watch out if you ever hit number 0 accidentally....you'll end up with a strange white cursor and all your previous shortcuts gone. It's some strange "keyboard only navigation mode" and can really confound you if you hit it by accident :)
BTW, the OP of this previous thread made a pretty cool video on this topic:
http://forum.cakewalk.com/FindPost/3220999