Adobe Premiere Elements is the budget version of the Adobe line (about 100 bucks or less with coupon). Anyway, it is a non-linear editor and also incorporates parts from other adobe products like Encore (for menu creation and dvd authoring) and also After Effects (for animations). It's sort of an all-in-one product. Of course you can incorporate the Adobe Photoshop Elements (budget version of photoshop) with this so that you can share photos and make cool slideshows, etc. I think it's a first rate product for budget minded.
I have used pinnacle in the past (version 8 and also 9) but i found that i had to run it like 5 or 6 times for it to actually render the movie since it would crash so often. this was disappointing. Plus, it was not easy to customize the transitions or animations. With Adobe stuff you can do that. Eg: you have a wipe from left to right as a transition - you can customize it to go from upper left to lower right if you want or also change speed of the wipe, etc.
I'm also fortunate to have access to the full versions of the Adobe products mentioned (Premiere Pro, Encore, After Effects, Audition). Well these are the sledgehammer products for sure and there are tons of books out there that help you learn the million features in each tool. I personally get a kick out of after effects since you can do cool things like fuzz out a guy's head in a video and composite in a blood spatter so you can fake his head exploding. sick example, but gives you a feel for what kinds of things it can do.
vegas is slick as well. my main minus is the lack (as compared to adobe line) of training materials available in form of books. go to Borders or Barnes & Noble and you'll see what i mean. I also have some other sony products like their music creation software and it rocks. the interfaces are very intuitive which may not be so for Adobe.
As was posted above, it depends on what you want to do. if you are making movies only for fun, stick with windows movie maker (free i think) or adobe elements line or sony vegas. i'd stay away from pinnacle only because of my experiences with instability. I had to put together a wedding video for my sister in law and used adobe elements line and it worked great. end product looked really good and the bride was happy with results.
good luck!