looking to upgrade my mobile phone i don't have a clue what i should get?

2-3 years ago i bought an Orange Vegas mobile phone when Orange were giving away free Skullcandy headphones and it was the cheapest phone eligible for the freebie i've never really liked or got on with the phone so want to upgrade i know i don't want a clamshell or slide type phone but from there i don't know what phone would be right for me my previous phones were both Nokia's i know i'll never be able to afford an iPod phone maybe i should try a smart phone or an android whatever it needs to be sim locked to Orange or unlocked wifi is desirable and at least do what my vegas does