Don't upgrade unless you have no choice. If you depend on PPC apps, then you must dual boot, buy a G5, or don't upgrade.
Anyways, 95% of the software for Mac in 2011 is either Intel only or Universal already. But I too have many older apps, but they never really worked well with Rosetta anyways. About 2 months ago I found the perfect solution... I bought a used Dual Core G5 with 8GB of RAM and the 7800GT PCIE and I can run everything I want at full native speed. This is a must in a production environment with legacy software.
Even under Rosetta, my Adobe CS2 and older versions of Final Cut suck big time and my ibook can't handle them anymore. So if you are like me, it is cheaper to find a good used dual or quad core G5 and run all those apps at native speeds (unless Rosetta worked well for you). It is cheaper than buying the latest Adobe Creative suite and Office 2011 anyways.
And many people tell me I'm stupid for using old software, but I have a 2011 iMac and just wasted $300 on the new Final Cut Pro X (trying to process a refund right now)... My old Final Cut 7 is a million times better and works great on that G5 too. I also use Logic Studio 9, and on the G5 it is smoother, on this new iMac, sometimes it tells me there is not enough memory to playback 14-20 tracks and crashes (even in 64 bit mode using the Intel Native version). Upon re-opening it, it works (sometimes). Never crashed once on the G5.
Now since I installed Lion on my new iMac, it is useless for my production environment... period (since Rosetta is gone). I don't want to buy office 2011 and upgrade all my current apps for $1000's of dollars. Even if I revert back to Snow Leopard and use Rosetta, the apps I mentioned are slow anyways, and often freeze or crash.
So I got a $400 G5 that works perfect for me and a $1500 iMac that's good for web browsing and iLife 11. (Well, at least video encoding with the latest Handbrake is more useful on this new i5 iMac, that is the only thing I can use it for daily)