I'm about 25 hours in right now, at the point in which I have the platinum chip and I need to decide which side I'm going to support when I realized that I really haven't seen or used any powerful guns or armor. The most powerful gun I have is the Service Rifle, and the best Armor I have come across is the Combat Armor Mk II. Am I doing something wrong or are more powerful things going to open up soon?

The service rifle is one of the more weaker guns. I don't know how you never came across the cowboy repeater, hunting rifle, sniper rifle anti-materiel rifle, brush gun, trail carbine and a bunch more of the shotgun, energy and handgun variety. There is power armour and other stuff better but meh I like what you have.

Sorry, I do have the cowboy repeater. The best gun I have is a 9mm pistol with a few mods. I came across the anti material gun at gun runners, but I mean come on....Who can afford that? haha

NCR Troopers always carry Service Rifle so from NCR's side you should expect high-power weapons when the Desert Rangers show up at around lvl 20+ (The guy on the box art)
But most places have fixed level spawns so to get high-powered weapons you'd need to buy them at Gun Runners or Van Graffs.
It's easy to get top tier weapons at Black Mountain at high levels as well.

But yeah most generic NPC's have fixed level spawns and won't carry anything better than the last time you killed them.
You'd better buy them.
There is Leather Armor Mark I, Metal Armor Mark I, Combat Armor Mark I and Mark II but most of those you will only find at Gun Runners.
Some generic enemies like Viper Leader or Scorpions can have Leather Armor Mark I though.

You can also get Remnants Power Armor if you complete Arcade Gannons quest.
And you can get Power Armor and the training required to wear it by helping BOS.

Plus you need 8 strength and 100 guns I believe. The best gun that I like is the sniper rifle with the suppressor. They won't know what's hitting them.

I see. My strength is only 6. I chose a build with high agility and luck. Don't get me wrong, I like the way it's playing out. I just sometimes miss the "Boom", you know?

Your weapon and armour availability is pretty much scaled to your level and what you have done.

At a point in the game, caps become immaterial - you will have more than you need.

Armour is only relative to how you play/fight. I haven't had much more than DT 4 or 6 for most of my game, and certainly not anything higher since level 8 or so.

There is a perk which allows you to lower the requirements by 2 if you need it. I think it's called weapons handling.

I'm going on level 20, and my go to weapons are still the 9mm and the 9mm sub. It just seems strange, but yeah, I guess it makes sense with the strength thing. I didn't take that into consideration when building my character. Oh, well, next playthrough I suppose.....

I was thinking about taking weapons handling actually. Will bigger weapons be more prevalent with that perk activated?

sounds like a good start. thanks gabriel77dan. Appreciate the help!!

No problem, for future problems try using the wikia: http://fallout.wikia.com/wiki/Fallout:_New_Vegas_weapons
It's a bit spoilerish but if there's something you're wondering about you can most likely find it on the wikia.
(Including locations to every single weapon in the game.)

If you have the hand loader perk (+50% damage .308 bullets) , the Sniper Rifle is the best gun in the game BY FAR. Add a silencer and it's the only weapon you'll ever need (except when they pat you down for weapons at the casino). The x5 critical multiplier means 6 Luck + boone's hat + finesse = 80% critical chance with every shot.

I think everyone is sort of overanswering and giving away too much info haha. Really the best answer is: there are more powerful guns and armor, and if you havn't found them, you havn't explored enough

Yeah definitely. If you don't meet a weapons requirement then it's accuracy will be quite lacking.

But you've already got your Strength as high as you need it. You don't even need the Weapon Handling perk. If you wear T-45d power armour, which you get for helping the Brotherhood of Steel, that will boost your strength to 8. Which is high enough to cover all weapon strength requirements except the minigun's.

Do some quests at camp McCarran to get "This Machine"... It's an awesome .308 semi-auto rifle.

It will one-shot giant radscorpions and kill deathclaws in 1 or 2 shots as well!

Rest assured more powerful weapons and armor are just lying around waiting for you to pick them up. Of course you're going to need some skills to get to them. High lockpick, and science to get in and some fighting skills to get past the bad guys and monsters.

There are a couple of powerful weapons that you can get fairly easily (some were already pointed out to you) including one not mentioned that is arguably the most powerful.

Rest assured more powerful weapons and armor are just lying around waiting for you to pick them up. Of course you're going to need some skills to get to them. High lockpick, and science to get in and some fighting skills to get past the bad guys and monsters.

There are a couple of powerful weapons that you can get fairly easily (some were already pointed out to you) including one not mentioned that is arguably the most powerful.