But you pay for XBOX Live additional to your costs for your ISP. But hey, who am i to tell you on what you have to waste your money
Actually, to the best of my knowledge any xbox 360 owner with a broadband internet connection has access to parts of xbox live (including the patches) for free. It's the online gaming part that costs a fee.
$50 for a year doesn't bother me all that much considering most MMORPGs cost that much for just over 3 months. Yes, PS2 and PC games are generally free to play online, but I feel the overall experience and extra frills are worth it for xbox live. (I do respect those who would rather pay nothing and have a bare bones game-only experience though)
On an unrelated note, I took the final line (Yes, this additional content will be released on the 360 as well. Further details about possible points cost of the extra content for the 360 has yet to be determined.) to only be in respect to the content, not the patch. It should still be free. As for the extra content, if they charge for it on the 360, I imagine they'll charge for it on the PC (much like oblivion did with it's extra content.)