tokyo feb 2008 itinerary

I'll be in tokyo from feb 12-18 (6 full days). Here's my itinerary-
Day1:ikebukuro (hotel),shinjuku
Day2:ueno/asakusa,akihabara,shibuya
Day3(yokohama day trip):motomachi chuugakai,minato mirai
Day4:tsukiji,ginza/yurakucho/marunouchi,roppongi/shinjuku
Day5:shimbaishi,odaiba,nihonbashi
Day6:meijijingyumae/takeshitadori/omotesando/yoyogikoen,shibuya

Appreciate any comments/suggestions :)

I want to suggest you as below.
Day1:ikebukuro (hotel),shinjuku
Day2:ueno/asakusa,akihabara,shibuya
- this seems too much for a day. Shibuya can be visited on a different day.
Day3(yokohama day trip):motomachi chuugakai,minato mirai
-the best spot in Yokohama is a traditional Japanese garden called Sankei-en, where you can see several historical houses brought from Kyoto and other areas, as well as the beautiful garden.
You can also have a sip of the traditional Japanese tea in the tea house.Take a taxi from Ishikawa-cho station of the JR Negishi line to the garden.
Day4:tsukiji,ginza/yurakucho/marunouchi,roppongi/shinjuku
-Too much to see again for one day. You can visit Shinjuku and Shibuya on the same day.
Day5:shimbaishi,odaiba,nihonbashi
Day6:meijijingyumae/takeshitadori/omotesando/yoyogikoen,shibuya
-If the whether is nice, I recommend you to go to the metropolitan government building in Shinjuku for the overlooking view of the city.

Thanks for your kind reply. For Day 2, shibuya does seem a bit of an overkill. As for Day 4's shinjuku, i might push that to Day 5 night instead (wanna enjoy the night atmosphere).

By the way, i am from Singapore. Would the weather be very cold & chilly? Coz that's what i'm looking forward to :) Singapore's too hot & humid to bear sometimes..