[Sundae]

I've given this a lot of thought.
It's really hard (meh) to answer, for the reasons stated by other posters.

The best lover I ever had, had the smallest penis. We had an exclusive but uncommitted relationship (no sex or dates with other people, but no love & plans - totally mutual). I don't know how I would have felt about a long term relationship with him physically. What he did, he did wonderfully, but I think I would have missed the actual feeling of penetration by an average sized penis.

The flip side is the man I obsessed over for years, who seduced me both with his tongue (verbally) and his huge cock (a secondary concern, but you do get used to it). It took me the best part of 8 years to deal with the relationship, and it was grounded in rollercoaster emotions and very, very good sex. I'm not proud of this, but he would call me up & offer me my train fare and £100 to come down to London to see him for the weekend. And I would go. And he owed me over £10k (in fairness, our estimates vary re what was a gift & what was a loan, but the fact is that he ended up on 4x my salary and didn't pay me back for years, claiming I would waste the money... which was true but irrelevant).

Anyway - I'd have taken my small-penised lover's tongue over anything from my lying, cheating, manipulative, silver-but-not-cunnilingus-oriented large-penised lover any day.