Are the Trijicon HD night sights any better than their regular (green) night sights? I like green sights, but I wanted to know if there are any quality differences between the two. Are the green night sights HD as well?

I think the difference between HD and their "regular" night sights is that the HD sights have orange paint around the front sight.

Triji HD's are simply variations of the original Hackathorn pistol night sights.  I've had more experience using these sights in widely varying conditions of ambient (sometimes dappled) light than most; and I've learned to strongly dislike bright, 'night sights'.  As far as I'm concerned Heinie, 'Straight Eights' are the best of the breed; but, by comparison, they are also quite expensive.  If you go the Trijicon HD route I'd suggest going with the orange front sight ring rather than one of the other brighter colors.  

One time I was charged by a fellow who came running at me through varying shades of light, shadow, and darkness.  Know what?  I, 'lost' him for one or two critical moments.  Where?  Behind the brilliantly glowing, bright green, Meprolight, front sight on my pistol.  If I had fired at that exact moment I would have put the first two rounds where the fellow had just been, rather than where he actually was.  (Which turned out to be a lot closer to me!)  

NOT a big fan of bright, 'night sights'.  

Do you have any suggestions on what to go with that are no more than $120?

 
It would help to know what pistol these are going on.  I'm able to offer this general advice, though:  While I don't regard them as particularly durable combat sights, with a little extra care, the following pistol sights are definitely serviceable enough for frequent use in competitive (IDPA/USPSA style) shooting matches:  

TruGlo Tritium Fiber Optic Pistol Sights.  These sights are a little fragile, don't have an outstanding product guarantee, and you have to be careful to keep many gun cleaning chemicals off them; BUT, they are more useful over a wider variety of ambient light conditions.  ('Night sights' aren't really for use at night.  In thick darkness they're next to worthless, too.  Most of them work best in DIM LIGHT, as well as on stationary targets.)  

I have Meprolight, 'night sights' on most of my pistols.  They're OK; but, looking back, I could have done better.  (Live 'n learn!)  If I weren't going to use Heinie Pistol Sights then I'd contact AmeriGlo Pistol Sights and ask them if they have an orange or yellow front sight blade/lens that could be matched up with a pair of green rear dots/lens?  

AmeriGlo makes a wide variety of popularly priced sights; and from everything I've been told, (and I'm around other shooters a lot) they:  stand behind their products, have a decent product guarantee, and the AmeriGlo tech support people are supposed to be some of the best in the business.  In Pennsylvania, where I live, AmeriGlo sights are very common; and I see them, a lot, on other people's pistols.

It is a G19 Gen 4. My dad loves to Trijicon night sights. I am not a big fan of the HD's since they only offer yellow and orange. I want the dots to all be white during the day and glow either blue or green at night

Ameriglo Pro sights are the only sight I use. I prefer the Orange outline on the front sight. It's fast for me to pick up.
I also prefer the simpler two dot tritium sight picture to the traditional three dot sight picture offered by Trijicon and most sight makers.