Denise,
The advantage of the Parkhopper plus passes is that unused days never expire, so if you don't use them all during your trip, you can save them for next time. Personally, we find that 10 days is just too much Disney for us - but I'm sure many will disagree. We just like to do other things while we are there.
If you go on the Universal Studios website, there is a internet-only offer of a 5-day Bonus Pass for Universal for $89.95 plus tax. It does require you to use the 5 days consecutively, though.
My advice is to make a plan of what you want to do each day (adding in some rest time!) and then work out from that exactly what tickets you'll need.
We learnt the hard way - and spent far too much on tickets on our first trip.
I hope that helps. I'm sure you'll get plenty more useful advice, too.
Julie