Mac customisation

The Leopard disk arrived and I duly upgraded. Immediately got the offer to set up Time Machine, but that hasn't happened yet - will do soon(ish).

Installed some of my favourite apps from experience on Win and Ubuntu:
Firefox
Thunderbird
Audacity
Clam XAV
Google Earth
VLC
Transmission

I'd previously used Open Office, but found Neo Office to be even more impressive on Mac. But what Mac specific apps to try?