Which ipod touch should i get?

to start things off i had a psp for music but i brought it to skool once and almost got it stolen by seniors(currently a sophomore, i almost got it stolen freshman year). so my sisters give me their ipod first generation after they got a nano. i didnt care for a nano 4 generation at the time, i was just happy to have an ipod but soon i realized how many songs i can actually put on it( only 130) and now that i do they dont sell them anymore. so i thought to myself y look for the old when i could buy new. I want an ipod touch to play my music and cuz it looks cool and cuz i saw my friend have it and he was able to put a gba game (pokemon) on it. how awesome is that(srry im not a techy so seeing something like that is cool). now that i have 180 and still saving i wanted to know which one should i get? i heard about something called jailbreakin and it gets u free apps and stuff but i also heard that u cant do that for the ipod touch 4 generation yet. but i want the 4 generation to use face time and talk to my friends. or should i just get a 3rd generation and call it a day?im very confused and on the verge of insanity since i havent spent any of my allowance just to get this so plz help me out. oh and can someone plz explain more to me what jailbreakin is, how my friend got a gba game on his, and is there any real safe way to not crack ur screen, i hear there are covers for the screen but friends have told me that they dont really work. help and thank you