Which applications to freeze with Titanium Pro?

Whatever you do not need. I also have CityID, Skype, Kindle and Mobile 3G that was pre-installed.
 
Besides Amazonmp3, Blockbuster, and Skype, is there anything else I should look at freezing?

Everyone's situation is unique, depending on what items you use. I froze the following:

Amazon MP3
Blockbuster
City ID
Kindle
Madden
My Verizon
News 2.2.1
News & Weather 1.3.01
NFS shift
Skype
Social Messaging 2.2.1
Social Networking 2.2.1
VZ Navigator
Weather 2.2.1

***I am probably one of the few who do not use the weather info on my phone since it is usually pretty nice here in Southern Cal.
 
Freezing? What about deleting? I have an app that does it,
SystemApp Remover. Should freezing be done instead?
 
Freezing? What about deleting? I have an app that does it,
SystemApp Remover. Should freezing be done instead?

If you delete, you may have to find them again or sbf in order to do an OTA update. If you're running a custom ROM, it probably doesn't matter because you either have a stock nandroid backup you can restore (with all the bloatware included), or you don't have that, so you have to sbf anyway.

If you are not running a custom ROM, freezing is easier. A frozen app can't run or use resources, but if you need to OTA, you just select unfreeze all (or something like that) and all the bloatware is back on the phone, the OTA works fine.

There is no point in deleting them because of space, as we have more than any normal human being could use on this phone.