I'm looking for stuff similar to Streetlight Manifesto. Any suggestions would help alot!

The Mighty Mighty Bosstones perhaps. Streetlight is unique in their genre.

Well obviously you should check out Catch 22. Big D and the Kids Table can be amusing, I Voted For Kodos are nice guys but since they lost their entire horn section they sound more like a ska-influenced pop-punk band. You'd probably like Aquabats. Most third wave ska bands are terribly repetitive and bland so it's kind of hard to come up with suggestions.

Reel Big Fish is pretty sweet too.

I'd have to recommend Attaboy Skip (<3), early Less Than Jake, The Mad Caddies, MU330 and the Mighty Mighty Bosstones to a Streetlight fan, though I prefer more traditional ska.

I agree with Ethan, a lot of third wave ska is more like pop music if you want to shake it up a bit try :

Capdown (early)
The Flaming Tsunamis
The Fad

or go mellow and remove a lot of that pop punk crap:

The Toasters
New York Jazz Ska Ensemble Band
Toyko Ska Paradise Orchestra
Ska-P
Ska Cubano.

Howards alias
 

You should listen to the first album by Howards Alias(the chamelion script)

The second album is not so good but is titled "The answer is never".

The band are on domino recordings.

i guess and obvious one is reel big fish , considering streetlight supported them on their last tour

man that was one awesome night.

Cougar90

The Suicide Machines
Madness
The Specials

ye the specials and madness aregreat if your looking for the classic original ska bands. not so much streetlight -like tho

Cougar90