I personally use PocketShield to lock my phone screen. It has the added benefit of unlocking automatically when the phone detects light, so it becomes pretty unobtrusive, yet prevents the infamous butt dialing syndrome.
If you ever want to get into flashing your own ROMs you can look at this wonderful thread.
http://forum.ppcgeeks.com/showthread.php?t=69854
I use MightyMike's MightyROM 6 which incorporates the new WM6.5 platform. Almost any custom ROM you choose will be better than the stock one. It's up to you to choose which suits you best. I chose MR6 because it had the most users. It must be good if that many people use it, haha.