I'm an enthusiastic guitar player and I have played for about 3 years now, and I need a new guitar. The price should not over 600 €. Any suggestions?
well, i don't know what style of music yu like to play...for

-> blues and rock i'd suggest a fender strat, or if it's too expensive a squier strat.
-> jazz of cource a semi-acoustic, like an epiphone es 335 or any kinds of it
-> rock/punk/r&r well, how about an epiphone les paul or a epiphone sg?
-> metal well, there are jackson an b.c. rich models that cost even 300 buck$

but you should go to the shop and test yourself. you can even play punk with a es-335 and play jazz with a b.c. rich, but you should take that model which sound you like most! why dont you look what guitar types your idols play? +
but i think most important is the pickup: singecoil or humbucker?
go out and try, nd don't forget about your amp! for a modern rock sound you should take at least 10" speaker, best are 12"!!
have fun!
You only live once, so give a **** and HAVE FUN!!!

Fender Fat Strat HSS
Les Paul Replica
Fender Frontman FM210R with 65watts
Boss DS-1
Korg AX3G Multieffect-Pedal