I also recommend g and g as a starter gun...in fact airsoft international magazine did a review this month on g and g egm a4 (its a h and k mp5 replica) and for 140 quid im a bit tempted myself!!!
No worries my good man.....I think they said airsoft world was the seller....helps if you know where to pay the money!!!
if ya fancy something you can mount accessories to I can highly recomen the g and g gr15 raider...its yet another m4 clone but if that doesn't bother you then you'll at least have the option for scopes,foregrip,laser,torch, silencer...oooohhh and an underslung grenade launcher!!!!
It depends what type of loadout your doing...if its cqb,then go for the mp5...the m4 is also usable in cqb but due to it sliding stock it can be used just as well in woodland/urban sites....plus if your using an m4 and scream "need a mag!!" then chances are you'll be battered senseless by the sheer amount coming your way!;-)
If you want to be like most of us a good G&G or SRC is what you need.
But I seem to have this balls to the wall urge to just go in with only a gas pistol but I haven't got round to doing it since I don't even own a sidearm. (Unless my springer counts)
Just want to add about the CYMA AK suggestion,get them over the '030' model,those are VFC and LCT clones and have great externals,made of stamped steel, and good internals.