i'm no japan expert and i'm sure zhi would be the one to ask but i'm bored at work about to finish an evening shift so. . . .
i would recommend that you check out ueno and kichijoji for kicks. ueno has a ton of stalls that have all kinds of shoes - one shop had a bunch of honolulumarathon kukinis - but i don't recall seeing tooo much older stuff there. kichijoji has k-skit (and la ave/napsize). visiting la ave is not the same sincenapsize online opened up. on my last trip i actually only found 1 good deal out of the tons of shoes that i looked at. maybe i'm a little jaded but goodluck on the shoe hunt.
harajuku/yoyogi park on sunday is fun. harajuku has some consignment shops and a ton of boutiques including atmos, supreme and neighborhood - stuff isexpensive there. check out all the elaborately dressed people outside the station. check out condomania. one phenomenon that i found interesting was the menthat dress up like young girls - maybe zhi or sgtshiz can enlighten me.
akihabara has all electronics including video games. to me the allure is not the same as the days of the sega mega drive and the nec pc engine. usa has caughtup with japan in terms of games. i didn't even go there on my last trip but you will have 10 days so... . .
i liked walking around shibuya. fricken shibuya is crazy crowded (especially to someone who was born and raised in hawaii). tokyu hands is a huge store thatsells ummm.. .. . everything!?! watch out because i got lost looking for a fishing store in shibuya and it took me over 1 hour to get back to the trainstation. the streets aren't linear in japan and the addresses are not in sequence
i guess would not be as bad for a newyorker though.
tsukiji fishmarket is a sight to see. it is the home to an amazing fish auction (blue fin tuna) and the stalls there are home to some of the most bizarrefish being consumed by humans. you can also buy some whale meat there (and all over japan actually).
roppongi was pretty cool the last time i was there but that was over 10 years ago and i'm no longer a big nightlife kinda guy.
i don't eat seafood so i end up eating a ton of katsu curry (pork cutlet with curry on rice with some ginger on the side). i really liked to eat thetonkastu (pork cutlet) at tonki in meguro and the menchi katsu (hamburger dipped in a kind of batter and deep fried) from kichijoji right by la ave. contraryto popular belief, food in japan is not that expensive if you know where to eat. one tip - plenty of restaurants have this system where you buy a ticket forthe food item you want from a machine and then redeem your ticket for the meal - weird.
i dunno though. i been to tokyo about 6 or 7 times and my favorite thing to do is just wander around and explore the side streets and check things out. to methat's the most fun part. i hope you have a wonderful trip.