This is a hand-me-down phone on which I had previously replaced the cracked glass on my 3GS (which, despite using the kit from iFixit, was a bit of a ugly mess, but I did it), but then shortly thereafter the LCD developed the "white screen of death" problem and I could never turn it off. Along with a dodgy home button, I figure it was time to replace the whole shebang and got the display assembly, as I probably should have done in the first place. $60 to get everything fixed at once (vs. $800 for a new phone)? Why not!
This was so much easier than the glass replacement, especially having already had lots of practice taking the 3GS apart to do the glass and battery replacements. The cost is higher, and there's the waste issue of throwing away a perfectly good screen, but it's a much simpler repair than replacing just the glass. iFixit's repair guides are indispensable, and the I love the magnetic project mat that I picked up as well, which is perfect for keeping track of those tiny screws.
Obviously, had I known my LCD was going to start failing so soon after the glass replacement, I would certainly have gone with the display assembly replacement in the first place. But having done both, I would recommend just going with the full display assembly replacement if the price difference isn't excessive.