I suppose some of it has to do with how much you are willing to spend. There are a few possibilities, each with advantages and disadvantages.
The least expensive I'd likely consider is the Optimus Elite, which is selling for roughly $90 on the VM website right now. It is a relatively basic phone but with enough power and memory to be a good starter phone.
In think the One V could be good, though it is a bit more at $120 currently on VM's site. For the money, it has some advantages over the Elite. One key factor is how the person would feel about having a built in battery; for some, not being able to replace the battery is a deal breaker.
In some ways I don't like the Evo V as a first phone. While it is a good deal at $150 (VM's site and at Walmart), the separate band for Wimax could be confusing to a new smartphone user (though would improve their user experience with better speeds). It also has the 3D, which while many people like it, is an extra item that would subtly increase the learning curve. There is also the radio issue that some Evo's are having, which has caused issues sending/receiving text messages.
I think for a first smartphone, they'd be better off with a 3G phone. I'd go with one of 3G phones and then upgrade, when they are wanting a better smartphone, to an LTE phone, which should be available in a couple of months.
Last, I'll agree that the Galaxy Reverb seems to be a good phone, though it is the most expensive of the 3G phones at $160 currently on the VM website. From what I've seen, people seem to have fewer problems with this phone than most of the other VM phones.
Of course, what phones people like tend to be based on personal preference. Another issue to take into account is what size phone they feel most comfortable with. While I'm getting comfortable with larger phones (larger than 4 inch screen), some people prefer smaller phones because they fit more comfortably in their hand. Others prefer the larger screens for readability. So much with how a phone feels in your hand and how it looks is personal preference.
Ultimately, what will be a good first smartphone is likely to be based on personal preference.