Advise, still on old baseband

[marc3lus]

I'm still running on 3.1.2 05.11.07. My iphone 3g is jailbroken, and i don't need it unlocked. I'd like to know if i shouls update to 4.2 or another firmware. Secondly, i'm guessing i will have to jailbreak my phone again, but using what this time?
And will i lose my cracked apps?

Any direction is appreciated!
Thx.

[Cer0]

Talk about cracked apps/warez/piracy is not allowed.