The 3 I would highly recommend would be 24, Breaking Bad and Dexter. Those 3 are all action thrillers I guess.
For comedy, I would watch The Inbetweeners (UK version) or The Office (US version)

Stop wrote People who are listing please list genre I'm also looking for TV series but I mostly like comedy

If you're looking for comedy then fresh meat is comedy gold.

Here's a few I've seen and really enjoyed;

Fringe
The 100
lost
Prison Break
Kyle xy
continuum
Terranova

Prison Break, That new show with Snoop Dog and his Family, Ridiculousness,

You could watch the wire its over but u can find it somewhere its about gangs its pretty good

1.The walking dead
2.Sons of Anarchy
3.Breaking bad
4.The office
5.The Wire

The best series I've ever watched is Dexter i recommend it.

Everyone is recommending prison break, I didn't see it as that good. Although I watched dexter and that was awesome. I'm going to give walking dead a go.

Cyprus wrote Everyone is recommending prison break, I didn't see it as that good. Although I watched dexter and that was awesome. I'm going to give walking dead a go.

I Hated prison break i think there both terrible actors and they took the show too far as if you can break out of prison 3 times