I do agree that quick identification can be usefu. One reason why I put the tablename first is so all items relating to the table are close together.
As far as underscores go. No real reason other than I had to pick something and tend to prefer UsingProperCaseNames to Using_Proper_Case_Names. Shorter, plus this is what MS decided to recommend for the .NET stuff. I always disliked the all CAPS stuff in C for constants. I know they stand out, but I've never had an issue running through code and checking variables. If I'm confused or new, I should be extra careful anyway before changing the code. Plus it's easier for me to just be consistent than to try and figure out if I should be making something all CAPS.
Not against it and if I worked in your shop, I'd adapt. Just what I decided was easier.
Steve Jones