IMO any e-bike with a front suspension will likely suffice. So it's a matter of finding one that suits the budget and other personal criteria.
It is pretty well accepted that disc brakes are a necessity on an ebike due to the higher speeds. And if you do any riding in wet weather then all the more reason.
The hub conversions are really setup for a disc brake bike, and while it can be possible to convert a rim-brake bike, there are a variety of complications, not the least is mounting the calipers. Frames originally made for rim brakes can be pretty lacking in support for the forces of disc brakes.
It is also pretty well accepted for larger tires, even balloon tires, as the assist overcomes any additional rolling resistance. Same deal, the added speed of the assist tends to create a need for additional suspension action, so you see balloon tires, front suspensions, suspension seat-posts, etc.
Do some more research here, and be sure to visit some of your local bike shops and look at what's for sale out there. Then come back and ask questions. Lots of help here - plenty of early adopters that can lend a ton of wisdom and experience.
We got introduced to the whole ebike thing by some friends that rented RadPower demo bikes and decided they wanted new ebikes. They bought a Rover for him and a City for her. I got really excited about the entire concept and started doing a bunch of research. I ended up converting her
Specialized Roll, and got a new Giant Explore for me. We're very pleased with them both, and the whole ebike concept is just fantastic. It got us back enthused about getting out for rides - really enjoying them and putting in a lot of miles would never have done otherwise.