Ubuntu 8.10 is out now - many incremental improvements to 8.04. Multi-monitor support better, HPLIP works quite well (encouraging to see that HP is making the effort to write a package for Linux), etc. etc.
I can't make wholesale "go for it" recommendations - although Linux has made tremendous strides in a very short time, one still needs to have a sense of adventure and acceptance in case that Canon scanner or Broadcom wireless card doesn't work. Read an interesting article the other day - apparently there's a growing movement among the device manufacturers to supply Linux drivers. That would help tremendously.
The best way to get started is to install 8.10 to a desktop PC that you have laying around as a spare. Maybe your kid's PC. They won't be able to ruin it anymore when they go to their bit torrent-peer sharing-free music download sites!