Well, $10K would go a long way to making my unfinished basement into a comfortable, inviting, useable space (including a small synth studio). But if we're talking gear...
1. DSI PEK
2. Some good monitors
3. a new MacBook Pro
4. Workstation desk
... further down my wishlist..
5. MackieControl
6. MackieControlC4
7. Apogee Ensemble