Question about Roku and the streaming life

I've been TV-less for a good while. I have an upgraded laptop that I use instead; Netflix, Hulu, Amazon Instant Video plus subscriptions to NHL Gamecenter and MotoGP.

I'm looking at picking up a Roku and a good size monitor and giving that a go as an upgrade to watching things on my laptop. For using a Roku, do the services I stream require a Roku enabled app to watch or does Roku have a browser that I can use to go to the MotoGP website (for example), log in and go from there? If I go Roku I'd want to know I wouldn't have to plug in my laptop for certain things.

Also, who offered the service where you can stream ESPN, CNN, Food Network etc for like $20/month. May look at something like that as well.