Need some advices :)

First, I'm sorry for asking this question. I know lots of people asked this question already, but I think it depends on your personal usage. So, I wanna ask some advices.

ipod touch 4g (32gb)
15.1 music (Usually increase by 20-40mb/months, I don't really update my library)
0.6 Photo (Going to have more with 4s camera)
0.2 Video (The last apple's keynote, not planning to keep it)
4.8 Apps (I don't use all of them)
0.6 Others (Anyone can tell me what kind of data tagged as others?)
7.2 Free

I'm an international student who goes to college. I'm not into photographic or making videos, just take some pictures (not often, when I travel only). I do like to listen to music even though my playlist mostly only 1-2 gb and I do like to walk when i have free time and listen to my music. I'd prefer to use my own storage to listen to music rather than using radio/stream it, especially with the slow and limited data from t-mobile i'm going to use. I don't play games, only play puzzle type games while waiting for the bus or friends. I won't use the extra memory for any other thing, I got a flash drive attached to my keychains that I bring all the time.

The question is it is going to be a phone, I'm thinking that it might use more storage room for the apps or the data. Do you think it's worth to buy the 64 gb one? Anyway, I work at school (part time job) and I get around 200-300/mth (100 more is not really a problem at the moment) which is free to use since parents paid for my school, however I do want to use the money to cover my school's payment too, I don't want to be spoiled by abusing the "firsts" money I earn. Also, I don't resell gadgets. However, I'm thinking about 2-3 years cycling, so, long-time value is not really a problem, since the features are what matter.

What's tempting me is that I might take more pictures and videos since the iphone got one of the best phones' camera. But, I do have experience with my dumb phone when I use a bigger memory card, it sucks more battery, and I do consider phone's standby and talk time which is one of the reasons why I'd go with t-mobile with their 2g!

Anyone mind to share their story who'd probably have the same dilemas?
Anyone have any suggestion what should I use the $100 instead of extra memory? (I'm going to buy the AC+, and I got Bose IE2, thinking about the MIE2i for siri though)