ETA: If you're planning on getting a TV subscription service here (Sky, Virgin, etc.,) you probably won't miss that much TV. Some things take a while to get over here, but others are only delayed a week or two. Some, like "The Daily Show", is pretty much the next day (albeit a truncated version). Even with Freeview you can catch a lot of stuff fairly current.
I agree - depending on what shows you watch, you may be able to catch them on TV here in the UK. Several of the primetime US shows are aired here in the UK only a few days (or maybe a few weeks) after they've aired in the US.
At the moment, we are getting new episodes of House (season 6) and Flashforward in the same week that they have been aired in the US, and from January they'll be showing the new seasons of 24 and Lost on cable/digital as well. The last few weeks, we've been able to watch Dancing With The Stars on cable just 4 days after the US live shows and in the New Year, we should get American Idol a few days after it's aired too. Normally we'd have Desperate Housewives and Heroes on at the moment too, but for some reason, they haven't starting airing the new seasons here yet.
Also currently airing in the UK at the moment are: Defying Gravity, Gossip Girl season 3, Fringe season 2, Lie To Me season 2, Big Bang Theory season 3 (starting this month), Bones season 5 and I've read that Glee will be shown in the New Year too.
Often the UK TV stations will start showing US shows a few months after they're first aired in the US (maybe in Jan or Feb) so that they can show the entire season in one go without having mid-season breaks between the episodes - so by the time we reach the end of the season, we are only a few days behind the US. More recently though, they've began showing them closer to the US airdate to reduce internet piracy/illegal downloading (i.e. if a show is aired in the US on a Wednesday, it will be on in the UK by the weekend).