I would think Facebook, Flipboard and *gasp* Safari are one of the most commonly used apps And their functionality representing the best the OS has to offer in terms of multitasking and memory management...
In Safari I'm greeted with white empty tabs most of the time which reload from scratch (takes a few seconds, even on WiFi). It's not a huge annoyance with forums, but the more content rich pages are a pain. Also, I have several tabs open (3 forums, 2 photo albums, a guide or two, local news portal) and trying to move between them triggers a reload too (very rarely not for one or two). Safari is the biggest offender here.
Flipboard loads and does return me to where I was, usually. But the reload is what annoys me. Chatting with friends and having to wait a second or three for the app to load again is far from fun too... Spotify doesn't suffer here, I don't remember it needing a reload when I'm checking what's playing atm
If only the device had more RAM, this wouldn't need to happen...I'd say 2GB for the most convenient experience.