Is it worth upgrading? It really all depends on what you do with the software. My advice would be to try out the 30 day trials before you go ahead and upgrade, then you can decide for yourself. There is no problem with keeping CS3 installed and installing the trials. Remember, though that if you do open a file you created in CS3 - don't save it back using CS5 or you may be unable to open it again if you decide not to upgrade. There's a ton of online stuff that tells you about the new CS5 featues if you go to the adobe site.

I think there is little value to upgrading two programs from the suite seperately - I think the total will be just about the same as upgrading the whole suite.

If it makes you feel better, the upgrade is even more expensive outside the US.

The suite upgrades are basically designed to move you up one level in future upgrade revenue. Of course the other way to look at it is that you have the use of the other suite programs at a discounted rate.

Whether the upgrade is worthwhile is entirely dependent on what you intend to do with the software and whether you can afford the cost. In my case I was forced to upgrade because as a freelancer, my clients were using CS5 and they couldn't send me files in formats less than CS4. Adobe knows how to make people pay out..

[Oh, I've never had a problem re-installing software on my machines - through machine upgrades or HD replacements ]