Good songs to play on guitar?

I haven't been playing guitar for very long but I would like to know some songs that would be good to play. The songs that I have been playing are "Good Riddance (Time of Your Life)" by Green Day and "Paint It Black" by The Rolling Stones. What are some other good songs like those that are at the same level and have good melodies or riffs or whatever you call it? And also I would like to know some songs that would challenge me more and help me get better.