I have been reading a lot about HTML 5 and some of the changes that it offers. It seems though that for most of my needs (LOB apps) it really wouldn't have that big of impact. But recently I had a designer friend of mine tell me that I need to start building everything in HTML 5 because that is what everyone is wanting now.
Can someone give me some good articles or point me in the right direction to really understand what HTML 5 offers me vs HTML 4?
If you're doing LOB stuff and nothing too fancy graphics-wize, then probably the biggest change would simply be using the HTML5 doctype tag:
Even on browsers that don't support HTML5 directly (e.g. IE7) this is interpreted as a valid DOCTYPE and the browser stays in "standards" mode. So as a starting point, that's probably the simplest you can do.
Then you can start looking at some of the additional attributes and so on that HTML5 brings to the table. Support for HTML5 forms is quite lacking at the moment (mostly it's just Chrome/Safari/WebKit and Opera that supports most of them) but it doesn't hurt adding them (they're backwards compatible).