Jack of Clubs, to represent me. Jacks aren't as flashy as Spades, black suits are more masculine than red suits, and I like being the power behind the throne.
Queen of Hearts, to represent the love of my life. Simple enough - it's the most commonly freely-chosen card by women during a magic trick.
2 of Hearts, to represent a relationship. I guess there are a lot of romantic associations with playing cards.
I do have a group of favorites that I like using for a card trick. I do a stunt using a stripper deck where I show a poker player how to cheat at poker - he deals himself four aces, but unwittingly deals me a straight flush. My favorite choices for the straight flush are the 5 through 9 of any suit but diamonds. All 15 of those cards have one-way faces, allowing me to insure they're turned the correct direction in the stripper deck before I shuffle. I enjoy the 8 of Hearts in particular because I have the WOW trick in that card!