one thing i found annoying was that whenever i used to receive a message via facebook chat, my firefox used to instantly crash with a message saying i need to update quicktime player. i hated this, especially as i didnt have any quicktime extensions etc...
now the same thing happens, except it doesnt crash, it still always asks me to update. i dont like quicktime.
firefox runs very slow on my pc cpu. it consumes a lot of the working memory and makes the pc performance very sluggish. im prety sure on v1-1.5 FF consumed a lot less cpu resources. my pc has a 512MB AMD Athlon 64+ processor, (1.6GHz i think).
laptop has 2GB Intel Centrino Core2 Duo, 2.0GHz. much smoother on laptop. HDD capacity is about 70GB more (2HDDs on laptop) and also i have more memory freely available and less applications/softwares installed. so these could all be contributing factors to system performance.
im waiting to upgrade my pc processor - requires new motherboard, secondary hard drive (1TB), may or may not upgrade to windows 7 (i quite like XP though; and i know if i get windows 7 i probably need an even better cpu for longevity and to keep pc futureproof - i.e. not slow down significantly after a few years).