Where are all the enemies?

I can't find that many random enemies scattered throughout the game when compared to FO3.

It seems like there are less dungeons or interior areas for NPC hunting too if not then where are they?

There are a few enemy factions like the powder gangers but they are very quest related.

Where are the more generic and random humanoid enemies to kill and hunt for loot and experience?

And yeah robots go on this list too?

Assuming you don't want to ally yourself with the crazy drug gang, there are always Fiends around to take pot shots at. Also, there are small pockets of Vipers in the wasteland that aren't really faction or quest related.

As for random super mutates, I don't think I've seen any around. None that I want to take shots at anyway after clearing out Black Mountain.

There are some humanoid enemies that can spawn in certain areas (Powder Gangers and Fiends, as well as NCR and Legion troops if you become their enemies), but NV doesn't have anywhere near as many completely random raiders and stuff like there were in F3 (probably because a number of people complained that it made no sense that 90% of the people in the Wastes were raiders). I don't think there are any random robots.

I guess this is more "realistic" and "traditional" that most human would join fractions. Although I do have to complain why isn't there a Viper base.

The other folks nailed it, Fiends, Vipers and Jackals are your best bets.

They all have camps scattered around, but fiends have the best look and they're all over the outskirts of Northern Vegas if I recall correctly.

Most of the ones you'll run across as well, are leveled. And they don't start really kicking in until you're past level 15. At least that's what I've seen while kicking through the geck.

Where do I find these raiders I don't mind a little hint or spoiler? I can't find a list on the net anywhere.

C'mon I need a push and a point in the right direction there are no online maps for the game yet.

Where can I find humanoid enemies in the lower part of the map?

On the east side of the colorado, To the south of that landmass.

Actually, Powder Gangers. so far most of us can't make friends with them after Goodspring,

if you want to find fiends every three days or so go to the area outside vault 3 there are about 10 to 15 of them and they respawn. they dont respawn i the vault though. pretty much anywhere on the north and west of the strip there are fiends

I haven't really seen that many hostile encounters apart from the Viper and Jackal gangs which jump out on you whenever you pass a bilboard

Theres a couple of quests that can get you back in their good books.

With the, albeit limited, amount of law and order provided by the NCR and before them the Desert Rangers, there will be no random groups of raiders wandering around the way they were in Fallout 3. The only raiding-type groups to survive would have to belong to large gangs with enough power to oppose the NCR, not small encampments like in D.C. As for Mutants, if you played Fallout and Fallout 2 you'd notice that the Mutants created in Mariposa kept more of their intelligence than the ones from Vault 87 did, and all the mutants in the Mojave appear to have allied themselves with either Jacobstown or Black Mountain. Thus, no random groups out to kill you. And since Vegas wasn't hit directly, less humans were exposed the amount of radiation needed for ghoulifcation.