I have Adobe Reader 8.1.2 and it really wastes my disk space. It's over 100 mb. Are there any small alternatives to viewing Adobe files? Because I don't want to uninstall Adobe Reader and end up with out a program to view adobe files.

Try Foxit Reader.

Downloadable here.

Foxit reader is a small and very well used pdf reader. Download size 2.1 MB's.
You can always have a try and see what you think.

http://www.foxitsoftware.com/pdf/rd_intro.php

It's an excellent alternative. I read some guys' critique of Adobe Reader. He basically said that it was like opening up a humungous ram-hungry Photoshop application in order to look at...a typed page. (I know there's pics in some pdf's but it was an exaggeration.) I never saw the appeal in pdf's. Navigation is horrible.

I prefer Adobe Reader myself because some of the third-party alternatives don't always display some PDF documents correctly.

However I use this to drastically speed up its launch time at the cost of a little lost functionality such as not being able to click URL's and open a website link in PDF documents, etc.:
Adobe Reader SpeedUp (freeware, no adware, no spyware, no viruses)

Thanks for the help everyone, I tried out Foxit, and I've decided that it's a whole lot better than Adobe's load of crap. Adobe is out my computer and Foxit is going in.

Adobe Reader isn't neccessarily bad. It's just so dang bloated.
The Reader Speedup app sounds good. You'd think Adobe would've incorporated something like that within Reader in the first place. But nooooooo.

Ever since Adobe bought Macromedia they've gotten fat.

For anyone using the Adobe 8.1.1 Lite I posted some time back, there's now an unbloated Adobe 8.1.2 Lite available.

Adobe 8.1.2 Lite: (Softpedia)