Well, I don't want this to sound rude, but would you rather have a phone or take a bit of time to set up your applications again? You may find you don't even need/want some of them anymore.
Plus, depending on what hardware is in your iMac, I'm sure you'll notice a decent performance improvement, as well as some awesome new features.
Like you said, you can also buy the box set for $100+ dollars and probably do a direct upgrade from that.
It's really not all that much work, back up your bookmarks, remember your passwords (which you should already) and back up your data. Simply copy it over after that.