I've seen discussion of filters and such like 2xSaI, and I'm sure the emulation devs intend to make the emulation look as fabulous as possible. They seem more concerned with run speed and compatibility though, so the window bling (which I think is adorable, by the way) is probably low on the list.
For web, it's been said that Firefox 3 should run, and that should satisfy much of your list. Flash support will be reliant on open source code. It's not fantastic, but it handles some basic needs.
There will be music players. There's been a lot of interest, so I wouldn't be surprised to see several different ones available, since everyone seems to have their own personal favorite.
There's been mention of Gnumeric and Abiword for spreadsheet and text/document editing.
Several people have mentioned Frets on Fire and other rhythm games, enough that I expect something ported. And for your tiny guitar needs,
this is rather cute. (Tried to link to the technabob review article, but it's down now.)
There were suggestions of other games instead of Command & Conquer in the forums. It's not open source, but you could play the PS1 version of C&C and C&C:RA.