Here is the thing. I got new SSD and want to run clean install of Ubuntu 11.04 on it. I have install usb which I made right after 11.04 was released. And my question is - should I now download again iso image to avoid lots of updates or this is the same version as it was before an I will have to update anyway?
Even if you download it again, you'll have to update anyway (there's updates almost every day so if the iso you download now was created some weeks ago, you'll have to update).
What you should do is install with your usb, and when it asks you if you want to download the latest updates from internet during installation answer "no". You can do it later from the desktop and it will be faster.
Let's say the firefox in your "old" iso is 5, and the firefox in the "new" iso is 6. It doesn't matter because the version in the repos is 6.0.2 so whatever you install it will be upgraded, and it will be the same clean install, don't worry (this is not windows, who gets slower in each update...).