If it is available in PDF format as well as print, WotC will get two sales from me. I don't have a problem paying extra for the added utility of having both formats in my library.
I'll buy one print PHB no matter what. If it's good, I'd prefer to buy the rest as a combination of print, PDF or electronic, and DDI style compendium. I loved that thing especially with the character generator. I would probably have multiple copies purchased if they were all available.
Ok, so it looks like a few of us are in general agreement here. With dndclassics.com I believe WotC have a good chance of supporting pdf's for 5E, what I'd like to see sooner rather than later is Mike using his Legends and Lore column to tell us some of the distinct plans they have for the release rather than talking about bits of the rules so much. For example are there going to be the traditional 3 core rulebooks, is there going to be a starter set, are pdf's going to be for sale? I think we're getting close enough to the actual release for them to start telling us some of this stuff now.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.