As you will have seen from the above threads there are very much two camps at play here.
One says get the Combat Machine because it's cheap, reliable, easy to maintain and there's plenty of parts available to customise.
The other says get anything but because M4s are the clitoris of airsoft (every c*%£'s got one).
If you're looking for something different then there is a whole world of weaponry out there. Which in itself can be a bit of a challenge because some of the nicest looking guns or more "unusual" guns aren't always the best performers. Something to take into account is also what gear (as in load bearing equipment) you might need. There's a far wider choice of kit available to work with the more common gun designs (G36's, M4's, AK's etc) but there's also a lot of - shall we say "generic" designs like the LBT1961 or the SAAV that will take all manner of magazines and bits and bobs. All depends on whether you're the sort of person that just wants something practical for the job in hand or if you want to try and recreate a particular look or load out. Very often trying to achieve a particular look will drive out the choice of gun - Brit kits dictate the L85, US the M4 etc.
The other thing to bear in mind is that while this is your first gun it's unlikely to be your last or indeed your only one. Airsoft is one of those hobbies that sucks your wallet dry at an alarming rate and if you get the bug then you need to expect to end up with a small armoury and more kit and gear than you could ever hope to use! For my money your first gun needs to be something reliable that won't put you off. It needs enough performance that YOU are the limiting factor not the gun. It needs to be a sufficiently ergonomic design such that you don't end up aching or chafed as a result of using it and it needs to have sufficient options for fitting the various bits of tactical frippery that nobody really needs but everyone wants. Finally it needs to have decent second hand value (both financially and in saleability) because let's face it - you might change your mind and decide that airsoft (be it the early Sunday mornings or the mongs that ruin your day or even the permanently empty wallet) just isn't for you after all.
A lot of those points will most likely drive you down the route of the Combat Machine M4. There's a very good reason why so many people have them and indeed why they are our usual "go to" recommendation!