I know security is a major issue for many people. I don't mean to discount your concerns. However, I think the whole security screen default is rather annoying. I do not like the idea of needing to enter a security pattern, or for that matter even a swipe to "unlock". In fact, I hate having the phone locked. Especially when trying to silence an alarm or notification quickly.
I don't like that The Android OS by default locks the screen and requires a swipe to unlock. I downloaded a third party app to disable this function. It's called "mylock" if anyone's interested.
There is also software available that can remotely diable your phone if it is misplaced. I use "Mobile Defense", it's in beta and could use some improvement. But, it is free. Also, a quick call to your carrier can render a phone virtually unuseable if it is lost.
I do see someone's point that even 5 minutes with an unlocked phone before loss or theft is determined could compromise a lot of sensitive data.
Again, not to discount your valid and appropriate security concerns - but, really - I think security is waaaay overrated when remote disabling software exists and one is mindful of not leaving the phone laying around where security would be compromised, what is the reason for the screen lock at all?
My Droid is either:
1. in my hand
2. in my pocket
3. plugged in on my nightstand right next to me inside a locked house.
The number one security step one can take is to just keep the phone on their person - problem solved. Unless someone actually grabbed it out my hand and ran down the street, I don't see how my data would ever be compromised. AND, if it was grabbed out of my hand, the screen lock would most likely already have been bypassed by me. Why would I EVER want the screen locked?
RE buttons being accidentally pushed: Is this really an issue? Push the top power button to put the device in sleep mode before pocketing or putting in holster. If you do this religiously and do not rely on the screen timeout to engage sleep / lock mode - you'll also benefit from extended battery life as the screen is on for shorter periods of time.