I would install the app System Panel first, as this will allow you to view which apps are constantly running in the background. From there you should have a general idea of what you may want to freeze. Normal apps like: AccuWeather, APmobile, MediaHub, Bubbies, Clock (all of them), Video Maker, Swype, Google Maps, Yahoo Stocks, Google Voice, etc, are usually safe to freeze if you rarely or never use them. But if you're new to Titanium, I would hesitate to freeze any of the phone's system apps, such as, com.samsung.internal, or status bar. And if you do plan to experiment, make a nandroid backup first to flash back to if things go awry. However, to avoid most of this I would install Calkunlin's Bare Rom or a similar rom, which eliminates most of the Sprint/Samsung bloatware.