Use hdmi equipped TV/projector as a Mac monitor

It is that simple. However your resolution will be 1920 x 1080, so the benefit of a larger than 27" monitor is minimal at the distances you would typically have a monitor.

New MacBook Pros don't have mini DVI; they have mini DisplayPort. You'll need a mini DisplayPort to HDMI adaptor (third party; Apple don't make one), and it will need to also have an audio connector since mini DisplayPort doesn't include an audio signal.

Yes you just need a mini-DisplayPort to HDMI converter cable for new Macs and a mini-DVI to HDMI converter cable for older MacBooks. There is no evidence to support that expensive HDMI cables (or DVI cables for that matter) with gold-plated contacts etc. are better than cheap ones. As long as the cable is built to a reasonable standard where it meets the appropriate safety regulations it should perform flawlessly unless you're buying the cable in lengths of 30 foot or more. There are plenty of tests out there to support what I'm saying, I've provided an image and link below to explain further.

http://www.40tech.com/2010/05/13/never-buy-expensive-hdmi-cables-buy-lots-of-cheap-ones-and-still-come-out-ahead/