Recommend/Request a Firefox Extension here:

[Scottland]

i've not used opera enough to know if this works or not..

but in ff if you have a folder in your bookmarks with all the sites you want to open inside that folder, middle-click the folder and all will open in tabs

You can also use ; as a separator for multiple homepage tabs.

Try opera, its got Tile, you can have it show you all open workspaces:

Cheers, but I've tried opera before and didn't get on very well with it.