Well, I've got this idea for two-thirds of a story---the beginning and end, but not the middle, which I've got to brood on some more before I start writing anything down---but that's not the point of this.

I've got an opening sentence...kind of. "I was talking to this guy at Chloe-and-Ed's party."

But I got to thinking---sometimes a terrible habit---and wondered whether it should be "I talked to this guy," which makes it feel more immediate.

Or maybe I should write it third-person. "He talked / He was talking..." Or "[name of guy] talked..."

I'm pretty much married to the opening: This guy talks to this guy at a party. Everything (except the accursedly vague middle) flows from that. I'd like to open with something like what I've written---but I'm not married to that. I could open with the conversation begun...have another person (Chloe or Ed) introduce them...have the main guy describe the guy and go over to him.

Then again, "talked" is perfectly fine too.

Then there are alternatives to the verb "talk"

From Roget's Thesaurus:

" 1. To engage in spoken exchange: chat, confabulate, converse 1, discourse, speak. Informal: confab, visit. See words
2. To direct speech to: address, speak. See words
3. To express oneself in speech: speak, verbalize, vocalize. Idioms: open one's mouth (or lips), put in (or into) words, wag one's tongue. See words
4. To put into words: articulate, communicate, convey, declare, express, say, state, tell, utter 1, vent, verbalize, vocalize, voice. Idiom: give tongue (or vent) (or voice) to. See words
5. To engage in or spread gossip: blab, gossip, noise, rumor, tattle, tittle-tattle, whisper. Idioms: tell tales, tell tales out of school. See words
6. To meet and exchange views to reach a decision: advise, confer, consult, deliberate, parley. Informal: powwow. See collect, meet, words
7. To give incriminating information about others, especially to the authorities: inform, tattle, tip 3 (off). Informal: fink. Slang: rat, sing, snitch, squeal, stool. Idiom: blow the whistle. See knowledge, law
"

I was talking - allows you to elaborate on the conversation. The story starts mid conversation.

I talked to - The story starts after the conversation, triggered by the conversation somehow.

Now, can you defend your choice to go with first person?

Yes, the beginning is very important and yes the rest of the story flows from the beginning. However, sometimes, the only way I've been able to figure out how the beginning should be written is to sit down and write it without worrying about phrasing or hooks or anything else. Just try to tell the story for a few pages. Sometimes I'll finish the entire opening scene before I figure out what I'm trying to focus on.

And then I'll go back and change POV or tweak/rearrange/rewrite/cut out phrases.

"This party sucks"

Or

"Is that shirt actually purple?"

Or

If your first line is "I was talking to someone about something" that's plain boring to me. Either start back in the party, when that was happening, or start with something else, and insert that information later. Or just get down to business and skip ahead a few sentences in the dialog when something exciting is actually being discussed.