For VST use, Roland modules are generally considered to offer the lowest latency, which is nice. I've found Roland kits to be basically plug-and-play, with out-of-the-box excellent triggering, once you tell the module which pads you're using. The nice thing about buying a complete kit is that you know everything will work together with a minimum of fuss. You could scour Reverb for the cheapest possible individual pads and module, and make it work.

There are a million ways to skin this cat, and none of them are necessarily wrong. I'd say some Yamaha and Alesis kits would be good as well, but I don't know much about them, so I'll let the others speak. There are tons of Roland modules that are pretty good for their price range, but I'd stick with the TD-17 for what you'd get for the price. The TD-17 is really good, you'll get really nice dynamics out of VSTs. Knowing that, it's good to remember that there are a lot of good modules with lower prices as well, so you don't have to spend tons of money to get the most of the VST. They will be better because they support digital pads, so if you're using Superior Drummer 3 as the VST for instance, having one of those two modules would improve considerably the feeling of your electronic kit. If your module is not good, you could end up getting undesired behavior, like double triggering, bad positional sensing, miss triggering, poor dynamics that could impact your playing style and so on. The module is the one thing responsible for interpreting the pad into midi signal.

Superior drummer 3 electronic kit