weird internet problems

[tetsura]

basically my problem is that my internet seems to work ok (on a WPA secured network), synaptic package manager and torrents seem to download at good speeds. but my browsers arent working properly. firefox sometimes works, usually the websites get stuck loading for a few seconds and then appear, but sometimes it wont connect to any. sometimes it also will connect to some sites but not others, for example i cant load google sometimes but can load other sites like msn. firefox wasnt working until i disabled ipv6.
i've tried opera as well but that wont load any at all.

im not sure if it's something to do with having a dynamic ip, when on vista i have a static one. (haven't been able to get a manual connection working in ubuntu yet)

sorry i'm not very clear, any help or direction would be much appreciated,
thanks

[tetsura]

i thought changing to openDNS had solved the problem but its happening again.

anyone have any ideas how to fix this?
thanks