I like the one already on the phone I don't need all the extras. I use heytel to talk to family that's pretty cool. My daughter told me she wishes she had not showed me it though. Haha
bitesms is my favorite too but is very buggy in 5.0.1 after jailbreak. and it interferes with editing a siri created text if you need to edit her dictation transcription before sending. try to tap on the bubble of siri's transcription and the bitesms' quick compose window opens up with NONE of siri's words in it. :-(
TextNow is a good free texting app that works great! It uses wi-fi or 3G and doesn't count against your ATT, Verizon.... account. The only drawback is that it doesn't accept incoming photos (attachments). Look it up in the Apple Store and decide.