I have an Apple tv and love it. I have fully sky tv but probably use my apple tv more. I jail broke my apple, this isn't very hard and this really turns it from a good device to a excellent one.
I have a flat in London away from my main home and the apple tv is also really good for this situation as I can easily unplug it and take it with me, also good for travelling aslong as you have access to Internet and hdmi whereever you staying.
As mentioned native Netflix has a nice app, you can rent shows as well or access shows via your iCloud.
Now for the excellent point, the jailbreak allow you to install xmbc media player on the apple tv, there lots of guides and xmbc is fast and stable. Through this you can access 4od, 5od, Itv player and BBc iplayer, iplayer is in HD. these list shows by channel and give lists of shows, high functional but not as nice looking as for say AirPlay. I'd say these give better aspect ratio and quality than AirPlay, BBc being prime example.
Another nice application you can get is veetle, this is user based web streams of shows, the shows change every so often. These are channels which show only one show in random order. Quality varies but is normally quite good but not HD. this is great for watching sitcoms when you can't decide what episode to watch. they often have family guy, American dad, south
Park, Seinfeld, king of queens, big bang theory, friends etc, they some times have docs and new drama series. These change though, you won't always get the same shows avaliable. I love this when I can sit back and just watch random episodes of Seinfeld, I would really struggle to pick an episode to watch from my sky box.
You can get also access Hulu, amazon prime, these require subscription.
Another good app is live streams, these are live streams of channels, this needs some config, but there are guides, some of channels are there dont work, but there are lots of good one which do, which are is HD, these come from a service called futubox, they don't encrypt there service, so a clever develop added the source to Livestreams to watcher for free, you access channels like hbo and Cinemax, sky Atlantic, comedy central, fx, fox, fox crime, these are all in HD and quality is really good, other channels include some sky sports, movies, and espn America, due to having sky I don't really use but good for others to know about.
I don't what your view on. File copyright and piracy is but if your liberal, two services called ice films, this is free and gives access to movies and tv shows, SD and Hd hosted on rapid share and 2sharec and furk.net, offers files on furk.net, pretty much any shows or movies you can think of In HD. Furk.net is 6 pounds a month so is not for everyone. For example on furk.net you could get hd new mission impossible, hd game of thrones, hd Spartacus.
Another service is tvcatchup, this is a epg guide and live freeview streaming of freeview, really good, this comes from tvcatchup and is legal.
I hope you look into this, even with just fully legal options you can get tvcachup and all catchups legally via xmbc. I would point out jailbreaking is not illegal, some people try and scare people away by saying it is, or if they are misguided , eg a noob in the area or are just against jailbreaking. Jailbreaking isn't hard as long as you are. Intelligent person, I have done it two of them one for me and one for my friend, he also loves his apple tv now, he you to spend load on DVDs, eg paying 60 on the wire box set.
Feel free to ask me and questions.