I have:
Maps
Gmail
Google Search
Google Translate
Places
Chrome on my MBPro. (Actually, I switch between Safari and Chrome)
I wish there is an iOS 4 version for Google Finance as well.
I set mine to lock after 1 minute. Even though I always have the phone on me, I can be absent-minded at times. It was tedious at first, but now, it'd feel weird if I didn't type in my passcode, lol.