Usually when I'm using game songs for my text message, I also go all out and set up my ringtone and email alert tone to the same theme. Currently, I'm set up with:
Incoming Call Ringtone: Title theme from Pokemon Red/Blue (GB)
Text Message: PokeCenter Healing sound from Pokemon Platinum (DS)
Email Alert: Pokemon Catch Success song from Pokemon Platinum (DS)
before that it was:
Incoming Call Ringtone: Bloody Tears from Castlevania II: Simon's Quest (NES)
Text Message: Player Death song from Castlevania III: Dracula's Curse (NES)
Email Alert: Level Beaten song from Castlevania (NES)
I'm about ready to change it up again, but I'm not sure what I want to go with.