The Clie's are great! My wife and I have our TH55's since 2004 and still love them. They get used it everyday. Last year I got her an iPhone 3G, but she still use the Clie. The iPhone is only her phone & TXT msg device.
I've got my eye on the Palm Pre, but am waiting for the GSM version. However, even after getting a Pre I think the TH55 will still get used. Maybe not as much, but it will still be around.
I liked the Clie so much I purchased 2 spares just in case we broke one. So if you want to get another Clie. I'd recommend the TH55! They're great!
Palm Pilot -> Palm III -> Sony Clie SJ33 (2) -> Sony Clie TH55/U (2) -> Sony Clie TH55/E (4)