High ping/latency - blame the hardware/software or the ISP?

I have a dilemma resulting from online play of FPS games, especially Crysis multiplayer. Using the Crysis' ping feedback which shows not only my own ping during online play but the others on my particular server, I find that more often than not I have the worst ping on the list, usually between 150 and 200. From the bit of reading I have done on the subject it seems that high latency in FPS games is a great recipe for frustration (I'm learning this first-hand).

Ive done some free web connection tests to determine my download/upload/ping speeds, and honestly my results are SO varied, some latency around 11, some over 200, depending on which U.S. server i select. I cant get a bead on why my Crysis online ping would be so miserable.

My ISP is Comcast cable and I live on Cape Cod near Boston, I dont use any routers so its a straight cable->modem->network adapter path (although I am splitting my cable wire for TV and computer use). My question to the community is if i want to improve my ping for gaming is it possible to software tweak, etc. to improve my connnection, or am I SOL because of the ISP I use?

Thanks in advance.

Agreed with the above. Running a trace route will show you where there's a bad hop. For all you know you might not have any bad hops, but your connection might be being routed halfway around the world and back.