@ eliyahu
if you want to play newer games circa early 90's fps or rpgs than a basic 500 won't do but like others have said you can get the new ACA 500 from Individual computer which has had great reviews though i'd recommend buying a case for it as your kids might be tempted to mess and that could be quite costly.
AGA is nice but there is a very small amount of games that were AGA only.
personally I much prefer my 1200 over my 500 simply because it takes up less space on my desk & the expansions are endless.