My computer is rounding the corner to 5 years old and is still kicking amazingly well. I had time to think about this when I came home to discover that it had fallen off its laptop desk and onto the floor, about a 3 foot drop. Fortunately it was closed but it put this nasty dent into the corner, a small crack, and now the battery compartment is effectively welded shut. The paint scuff is from before.
Also, the screen casing had cracked a few months ago and I had it held together by some tape but it was getting worse so I broke out the handy super epoxy and gooed it up. As good as sort of new! Nothing says award winning industrial design than shoddily applied epoxy.
Also, some pixels on the screen "dance" some times, and the CD/DVD drive only reads DVDs and don't even think about burning stuff. (I have an external drive I use for that)
BUT, that is with 5 years of nearly daily use and highly mobile use at that. And intensive use still with photoshop and flash. The original battery holds up for 3+ hours still. So nock on wood and three cheers for my trusty Ti Book!
UPDATE: I guess I have a lot more wear and tear to go through before I can really start to appreciate it!