infinity play kernal was a good mod for me. increased mobile data connectivity, i noticed HSDPA was connecting in places i didnt get before.
also new flashing new radio to get gps.
And custom MTD partitions. I got 100Mb extra internal storage space from the system that it wasnt using.
Simple things, but useful.
PRIMARY : SAMSUNG GALAXY SII
[RECOVERY]:[184.108.40.206] ClockworkMod Recovery
[ROM]: [9.0] CyanogenMod (Android 4.0.1)
[KERNAL]: [5.4] CF-Root-SGS2_XW_XEN_LP7-v5.4-CWM5
SECONDARY : MOTO DROID RAZR
[ROM]: [10.1] CyanogenMod (Android 4.2.2)
Hit the "thanks" button if i've helped you