chris, mate, it depends, if you want a gun that you could have tons more fun with at a site then go for a Mid/High range gun. if not go for a gun, EG the DE AK47/M901c
me and a guy i used to work with were installing cctv at the old lec refridgeration site in bognor regis (to stop the "do what you likeys" robbing the place) when we thought it would be a laugh to buy some bb guns from the local surplus shop and have a battle they were single shot spring pistols shaped like m9's. it was the most fun i have ever had at work this was before i even knew airsoft existed. and thats what helped hook me to this, remembering how much fun i had with them.