Apps that have been updated after 2008. I'll start and end there. Namely Skype and Fring since they're out for both. Apparently - as brought to my attention since I had stopped waiting on a fix sometime last year - RTComm had been updated.

Pidgin is still stuck in 2.5.x when the desktop is at 2.6.2 - but that doesn't mean that the libpurple is that far behind. I guess.

In all fairness, the whole telephony slant though is not really a big difference in my opinion though.

I'd say games is the biggest difference.