I installed Fring on my n810 with absolutely no issues what-so-ever, however although it is a nice app - it seems more limited than Pidgin. At least with Pidgin I can;

a) Hide offline users.
b) Disable the annoying beep every time someone messages me (flashing the LED is a lot more pleasant)
c) Have more than one of each account type running (e.g. I have two MSN accounts).

True I can't SIP with Pidgin, but Skype is better for my voice chat requirements - and at the moment nothing really hits that video sweet spot (I need MSN/Yahoo video chatting - come ON pidgin devs, you know you guys *want* to do it )