Because this is a difference of about $20 bucks in terms of buying it again.

I've played and beat the game several times, but just have the itch to play it again (that and I only need 4 more trophies to have all of them). On top of that, I have some saves from my previous playthroughs and wondered if I would be able to utilize them with a standard copy of the game or if I would need to get the GOTY edition in order to play the content.

I hope this makes sense. Did a quick search and hadn't seen anything.

Thanks!

Yes and no. If you've beaten the main quest, it will glitch out. Otherwise you will just lose the new content. You talk about trophies so are you intending to play this on an XBox?

Nope - PS3.

So, if I were to start a new questline from the beginning, I will not have access to the DLC. If I continue in a saved file that is in the middle of the main quest with the DLC, it will be there, and if I've already beaten the main questline with the DLC and try to load anything after the DLC comes in, it will glitch out?

Pretty much. If you aren't into the "Broken Steel" timeframe, or in any of the DLC worldspaces, it should work just fine. At least, it's the same engine, and it works find on PC.
You might want to make sure you load a save game that isn't actively doing something that the DLCs add. Make sure you are inside in a normal cell that was in the base game, you know?

I don't guarantee it won't have some bugs, but it should run fine.