I haven't made many bloody mary's but a friend and I went to a brunch place that had a bloody mary buffet table. Pay $4 or $5 for the shot of vodka and then have at whatever you like. And in two trips up, mine beat his hands down both times. And I have generally good luck mixing drinks, anyways. So for whatever it's worth, here's my suggestions.
I like tomato juice vs. V8; it gives it a fuller body. Less thin. Horseradish is an absolute must. A few dashes of worcestshire sauce is a must. Try olives and celery. See which you like better (maybe both). Celery salt is good to give a little bite. Ditto for hot sauce.
In my drinking experience (much broader than my mixing) a good bloody mary is hearty and spicy. Hearty in the sense that it's thick, like a cream of tomato soup and not thin like a glass of pop. And it also has a strong bite which can come from a variety of sources. With just a bit of tang. If I were you, I'd take a pint glass, put ice up about 3/4, throw in a jigger of vodka, throw in tomato juice up to bring it up to about 85% full, and then try various additives, stirring and sipping as you go along. Works for cooking. Works for drinking.
Other possible additives: pearl onions, black pepper, lime wedges, stuffed olives, jalapenos, A1 steak sauce (I think), wasabi, lemon juice, and beef stock(?) (suggested by one guy).