Is 15mbps with TWC fast enough for me?

I'm trying to set up Internet at my new apartment today and I saw TWC has basic tv & turbo Internet (20mbps) which I thought about getting, but they've also got digital tv & standard Internet (15mbps) for $15 more. Is standard (15mbps) fast enough for me?

Further details on my usage: It's just me with a laptop, an iPhone, Xbox & tv (WD TV Live media player too). I don't online game with the Xbox at this point but might in the future. I download a lot of movies & tv shows, but may not have to download as many shows with digital tv & just watch them when they're on. I use Skype to call family on occasion, watch Youtube videos, and spend a lot of the time just "web browsing".

Added (1). By TWC I mean Time Warner Cable, just in case that wasn't clear haha

15 Mbps should be enough. I have 18 Mbps and
it's way more than I actually need. I ran with 6 Mbps
for 11 years and did okay for me.
Don't take it wrong, of course more is better and faster.

15 mbit equates to roughly a 1.875 MB/sec transfer rate (8 bits in a byte).

Whether that is fast enough is up to you. Personally I would be unhappy with a package below 50 mbit.