Hey, I was like you just 3 months ago. Now I'm rockin' TweakStock 1.4 with PBJT Kernel. I can say that TweakStock is fantastic, but I haven't used other custom ROMs so I can only compare it to the garbage that is the Verizon/Samsung software.
As for the PBJT kernel, I'm kind of on the fence with that one. I've been experiencing more lag and more forced closes using it than with the stock (Verizon/Samsung) kernel. It seems odd to me since it should be running faster and not slower, but that's whats been happening. I did not update my Kernel to EXT4, still using RFS, but that doesn't explain why the stock RFS kernel runs better than the PBJT RFS kernel.
Note that installing a custom ROM will wipe your phone's internal memory but not SD card memory. Installing a custom Kernel should not wipe any memory, at least PBJT did not wipe my phone's memory.
There's a nice guy named trparky who has his own site dedicated to the Droid Charge. That's where I went to begin rooting and ROM-ing. You can find the website here:
http://www.toms-world.org/android/
I highly recommend that you click every link and read everything, not just skimming, but reading and understanding it as best as you can. If you have any questions, the last link will lead you to a comments section and you can ask him questions yourself.
Here is a massively long thread all about TweakStock it should provide a lot of info:
[Ep4D][Rom][Cwm][Odin]TweakStock v1.4 UPDATED 2/4/12 - xda-developers
I was perfectly happy with TweakStock and the stock kernel, supposedly PBJT has better battery life with it (I haven't noticed much of a difference so far), not sure if I'm going to stick with it or not.