I would say that these apps are a must:
- uLaunchELF / wLaunchELF (there are many variations)
- RetroArch
- Simple Media System (SMS)
- Open PS2 Loader (OPL)
- XPloder HDTV Player
if your PS2 don't have a mod chip
- ESR
- FreeMcBoot (FMCB)
- FreeDVDBoot
- FunTuna
I can't really tell you what's good, but I have ulaunch.elf, sms, and codebreaker attached to 3 of the 4 L/R buttons. I'm also using a hard mod though, which I just tested again after not using the system for several months. everything still works perfectly.