I say definitely AppleTV. Even if you don't like what the iTunes Store has to offer now, you can rip your own DVDs, download video podcasts or wait for Apple to up the quality. It just gives you so much more to work with in the future.
You can stream music to the AppleTV over 802.11b and video over 802.11g with no issues at all (provided you have a moderately strong signal). You can even load your music/video onto the AppleTV so your computer doesn't need to be on to play music. Best solution ever.