We find our cable speed to be great for us, 25/12 or something like that. That is the fastest speed available to my house. This is with multiple computers playing online games, watching movies, etc. Before that we had 16/3 (or close to that), and that worked fine.
My wife also works from home most of the week, and our cable speed has never been an issue - it is plenty fast enough, she has never noticed any problem relating to speed.
When we had DSL, it worked. Watching a movie came with "buffering" breaks a few times during the movie, where it paused for 30 seconds or so to pre-load some of the movie. It was fine for us at the time, and it freed up our land line phone from internet use.
If the house you are looking at is one you really like, but "only" has cable internet, I can't see letting that stop you from buying it. Also, internet speeds are regularly being increased as time goes on.
