I've been teaching myself how to play the guitar for about 7 months now and I'm just about starting to get stuck on songs to play on acoustic.

What would you suggest??

(preferably with more complex riffs and strumming patterns but anything will do)

Anything by tenacious d is hillarious and fantastic on Acoustic. Listen to kickapoo by them if you don't mind bad language too much.
for complex, musically stimulating stuff on acoustic you could always try some chili peppers stuff. scar tissue is a favourite of mine to play, but dani california is a really good one too. the guitar work isnt too fast, and the chord changes will give you a lot to practise. under the bridge, of course, is a common one, but definitely worth learning.

i found a lot of john mayer stuff to be really challenging when i started learning on acoustic, i mean going through some of his songs on acoustic will keep you busy for months.

how about some blues? angel, by jimi hendrix, is insanely complex but incredibly smooth sounding.

depends what kind of a player you are, pride and joy by stevie ray vaughan is a good one.

i realise i have no idea what you've already learnt, so those are just the kind of songs that i stuck to, which taught me a lot.
Drive - Incubus
Any Green Day
Touch Peel and Stand - Days of the New (Awsome Acoustic solo)
Thanks so much for the songs!
I will definetely go through all of them. Recently I have been playing a lot of foo fighters so this will help a lot to expand on what I can do.
Kansas - Dust In The Wind
Fender MIM 60th Anniversary Strat
Freshman Apollo Electro-acoustic
Line 6 POD HD500
Marshall MG15CD
Basically anything from John Mayer.
Legs - Jer Coons
Taylor - Jack Johnson

Try those.
Eh Lol
A Beautiful Mess - Jason Mraz
Constellations - Jack Johnson
Stop This Train - John Mayer
Angle mine by cowboy junkies is beautiful on the acoustic.
2010 Epiphone Dot
2010 Gibson Les Paul Studio Deluxe
2009 Taylor 110 acoustic
Try John Mayer- Love song for no one, easy but it has some interesting chords and strumming patterns
Interested at all in classic rock? At 7 months in I'd try House of the Rising Sun (The Animals), Wish You Were Here (Pink Floyd) and if you want to get crazy, Over The Hills And Far Away (Led Zeppelin).