I had a music issue during the mission from Novac where I check on the nearby ranger station. Upon entering the ranger station there were a few things that caused instant death and a reload of an autosave. The music wouldn't stop playing into the next reload, but also a new instance of the music would begin playing. After several deaths, There ended up being multiple instances of the same radio station playing, just offset by the amount of time I took me to die again. I counted up to 4 separate instances of the same song offset by a 30-60 seconds. It was weird.
I also had an issue where I visited a main town (not sure what its called, east of the starting town where there are lots of signs of warning about death claws) and upon entering the town, there is a single death claw and lots of named and unnamed dead npcs. It didn't seem right to me that named NPCs should be dead before I even had a chance to meet them. Luckily the deathclaw killed me instantly and I reloaded to a previous save. I didn't go back there, but I'm sure that town is still a dead town killed by a wandering deathclaw that is far stronger than any of the NPCs in that town.
I've found instances where NPCs will be "floating" several feet off the ground and moving like they are on the ground.
Radscorpions no longer have faces to shoot. Not so much of a bug as an oversight from the previous game. I have yet to figure out how to effectively take them down even with entomologist. I end up using entire runs of ammo (200+ bullets) just to take a single scorpion down on normal difficulty. Maybe I am just doing something wrong, but there aren't many places to shoot at that aren't heavily armored or ineffective. I should point out I'm using a service rifle mostly. Haven't tried lasers or heavy weapons yet.
Along the lines of creatures, there are these dragonfly looking things that I cannot seem to kill at all. VATS says 95% chance to hit on body, head, etc, but when I activate, nothing hits them. I've tried this many times now and they seem to be immune. I've also tried shooting them outside of VATS (which is pointless in NV for some reason... didn't have this much trouble in FO3, but whatever) and even when I get a hit, their health doesn't seem to go down. I don't know what the deal is. Again service rifle.
One other thing that isn't really a bug, but has annoyed me with Oblivion, FO3 and now NV is the lack of a periodic autosave. Often times, especially in the beginning, things are far stronger than you and you will unknowingly walk into situations where you are greatly outmatched and can easily be outrun and killed. Then, you die and go back to when... a half hour ago save that was the last door you exited. I never understood why a 5-10 minute periodic autosave would be such a tough thing to put into said games and why it's not standard in this day and age (including games that aren't gamesas related). I guess it would have to make sure you weren't "in combat" before autosaving, but thats pretty simple as the game engine mechanics are already in place. It just makes exploring not fun by punishing players to do so. My perception level in NV is about 7 and most of the time, I dont even see enemies before they know I'm there. And reaver ghouls can easily outrun you and kill you long before you can harm them to any great extent early in the game. Anyway, needing to save manually every few minutes takes away from the "adventure" and I typically forget to do so in a timely fashion.
I have also experienced misc. problems with the radio stations, including a constant static messup that sounds like choppy/jumbled music. Do you have a location on the Floating NPC's? As for the Deathclaw that wipes the town out that's most likely a bad spawn location, I think a lot of enemy mobs have semi-random spawn points in relation to you. Just last night I had a pack of agressive Bighorner's inside the CRNCF prison. Was nice though I could shoot at them through the fence for free xp. For all Radscorpions its good to have anti-armor bullets and high dps weapons with multiple shots (like a rifle) The Cazadore are high level bugs that can be a pain, VATS is terrible at shooting things that get really close to you, so things that get to you in like 3sec its worthless for. I'd suggets a shotgun or maybe machine gun / LMG with hp bullets for them, also they're a higher lvl mob so dont waste your time early on them. Finally if you find yourself being chased by overpowered enemies you might try the Tiger run tactic and move in a /\/\/\/\/\/\/\ left/right pattern I've found on things faster than you moving like that tends to make their attack miss, also holster your weapon if you're not using a pistol as that can slow you down. If you still die just reload to an earlier save and avoid the area. Hope all that helped =D