我想去大陸學普通話,去上海定去北京學好呢?

I think... I will pick peking.
reasons:
1. 上海's living expense is very expensive, and the city is very commercial; even the traffic is not as good as 北京.
2. 北京university is big and the students are very friendly, the atomsphere is much better for learning.
3. 北京 is capital city, the taxi driver, the subway, the police force, the medical items, the living environment is much better than 上海.
4. 北京's citizens are very friendly, you can rent a house or room in board or join those tours from HK's travel agents.( room in board don't charge too much), goto www.yahoo.com.cn chat with those U students, they may have better offer than you can imagine, I am sure they will find a place for you to stay.
last word, learning is different from study. when you stay there, live there, learn from your daily life is much much better than study books.

Good luck

當然是去北京!

普通話根本就是北京的方言，一般市民說的都是最純正的普通話。

而上海本身的方言是上海話，一般市民雖然都會說普通話，但一談話都會說上海話，正如香港人或廣州人，日常交談只會說廣府話一樣。

學普話當然去北京
普通話是以北京語音為基礎，而在北京學普通話的好處就是你可以有機會和當地人用普通話對話，而北京人講的恰恰就是最地道的普通話，在上海就不會有這樣的語言環境．

北京!!!!我本身係上海人,上海人唔喜歡講普通話~
而且普通話是以北京話為基礎的