Question re: effect of new wp versions

[vickivanv]

One of my friends is interested in rebuilding her site on wordpress using a rev2 theme, but is concerned about whether the theme will break when she upgrades to new versions of wordpress. How does that work--is it necessary to also install an upgraded version of the theme when wordpress is upgraded, or do the themes still work when new versions of wp are installed? I know new versions of wordpress will sometimes break the plugins, but I'm focused on what effect new versions will have on the theme itself.

And I noticed that Brian is working on a anew theme that is compatible with 2.7. Is there any information on when that will be out? Will that work better with 2.7 than the current Rev2 themes? Sorry for my utter noob-ness! I just want to give my friend a good idea of what kind of maintenance/upgrade work she should expect to undertake if she rebuilds on a Rev2 wordpress theme.

Thanks!!