Rooting question that hasn't been asked yet.

I have an UNLOCKED Nexus S. Got it from Amazon. I used this to root it.
[GUIDE] Simple, Non-Destructive Root for Nexus S i9023, i9020A and 4G Gingerbread - xda-developers
Worked fine- got rid of stuff I didn't want.

Next thing, here comes ICS update from Google. Needless to say, that unrooted the phone.

I also have a rooted SGS4G that was rooted twice - once with SuperOneClick, and Gingerbreak after the update. Stripped out all TMO garbage, plus social media and maps.(only maps I want are star charts.)

I bought Titanium Backup for the SGS4G and I want the usage of that back on the Nexus. I don't think I downloaded SuperUser for the Non-destructive Root. TB was working.

Most of the rooting instructions seem to be for a new root - TB and some of the other stuff is still on the phone. I noticed a difference when I re-rooted the SGS4G since it had been rooted. 2 systems for rooting: http://nexusshacks.com/nexus-s-root/how-to-root-nexus-s-or-nexus-s-4g-on-ics-or-gingerbread/
and:
http://www.techzek.com/how-to-root-nexus-s-on-android-4-0-4-ics-firmware/

I really don't think a custom ROM would do much for me. Which system would work better?

The phone is a PDA with Nature information, Astronomy apps, etc. I don't care about games, social apps (I will use Twitter, but will also freeze it until I want to use it again. It has no exit) I'm paying a carrier for service, and I'm happy with most of the service. So I'm not looking for freebies, just control. I bought the phone outright and feel I am entitled to use it in any LEGAL way I want.

Ice Cream Sandwich runs pretty well on the Nexus S. Why not change to a modded ICS ROM?

I might be looking for an ICS Rom. However, I've had a few strange issues - nothing drastic - with CM7 and gapps.

I was getting dual messages. Try to turn off the default messaging app, can't find it. TB can't find it, ES file explorer can't find it.
I also have a music player which is useless. It won't let you tell it where music is stored. I've used other players, and they at least, hunt out every MP3 they can find, regardless of where it is located. Not this one. I also have a weather and news app that wasn't on the phone to begin with. I think all this extra stuff came in with gapps, and they are all lumped together so you have to have them. I can't get rid of them. They are all version 2.3.7 - I had ICS when I rooted, so anything legacy would have been 4.04

Now I'm slightly confused as to what you back up. I posted in the CM forum, and got a mention that TB wasn't that great.
I see another post that says if you use CWM, you need to restore the same ROM you saved and had to be using that ROM currently or you got a loop.

So - I can back up, no problem. I now flash an ICS ROM, and either it doesn't work, or I don't like it. How do I get back to CM7 if the backup ROM and current ROM don't match?

I will say - CM7 saved me a lot of headaches. The wiki for using was great, complete, and written in understandable step by step English.

I got Root, Recovery, no problem with anything on phone memory - but no SD card. CM7 got it back. Phone never stopped functioning as a phone.

You dont actually need to restsore to the same ROM. Thats what makes Titanium Backup so awesome. I have the PRO version and its MORE than worth it. To safely back up apps from Gingerbread and restore to Ice Cream Sandwich, just backup the app itself, and not the data (although data should also be fine). As long as you arent backing up system apps from Gingerbread and attempting to restore them on ICS, you should be fine. System apps are highlighted in RED on TB, so if its red, dont back it up.

To quickly restore your entire OS, go boot into recovery and make a Nandroid backup. That way if you dont like ICS (trust me, you will), you can simply boot back to recovery and restore your Gingerbread ROM with all widgets and apps as you had it before. You should ALWAYS do a nandroid backup if your flashing a new ROM.

Remember, Titanium Backup is for backing up/restoring apps. Nandroid backup is for backing up/restoring your COMPLETE operating system including apps and data.