in urban europe 24mbps is considered subpar; what you yanks have, is frightenly slow.
24 Mb/s is pretty good for most any everyday household use, assuming it has consistently low latency and no packet loss.
The real question you should ask your ISP is: what's the network like when the weekend Netflix streaming surges kick in? Or: is my friday night deathmatch going to lag terribly? Of course if you ask that of their sales people you'll get blank stares and answers along the lines of "Netflix and games work great".