My 5th Generation iPod developed some lines in the screen a few years ago. It was still usable. I normally have it plugged in while I use it in the truck so the battery was never used much. But finally, after 6 years on the original, I noticed that the run time on battery was below 4 hours.
The battery on my wife's 30GB 5th Gen was also getting to be a problem. This was the 3rd battery for her. So we ordered new batteries for both and a replacement screen for my 60GB.
The repair went well and I had no problems with either iPod. The little clamps that hold in the ribbon cables are delicate. Be careful. Both repairs took about 20 minutes total.
In the screen replacement procedure, there are six tiny screws that hold the assembly to a frame that must be removed. These screws are extremely small. Be careful not to accidentally lose them. If they were to fall in the carpet you'll never find them again.