Like I said earlier... I would, but the monthly payments really throw me off.
Well, for 20$ you can get Half-Life 2 (an AMAZING game) bundled with counter-strike source. There is no monthly fee.
But addressing your original question, CS is the only game franchise that I have consistently played all my life, and you should definitely get source. Personally I like 1.6 better, but for a new player source is definitely the way to go. And two amazing games for 20$, its hard to get such a good product for the price (except for flashcarts lol).
1.6 is, I think, 10.
Yeah, there is a patch for NoSteam to play on cracked servers.