TTCing right now and it's starting to look good (won't know for sure until next week) - I just can't kick the coffee habit. I was so good when I was TTCing for DS...I was able to cut down from 2 travel size cups of regular to decaf. This time, it's just harder because I have a Keurig machine and it's so easy to grab a cup, plop it in the machine and brew it in seconds. I keep telling myself...don't buy any more boxes, start drinking half-caff every day, drink decaf. I keep buying the regular...and this morning I got a medium Iced Coffee and donuts. Gee..talk about falling off the wagon. Please tell me you are drinking coffee too...just a little?
DS born 2009
BFP#2 ~ 8/2/11, EDD 4/11/12, D&C 9/12/11 at 9w5d
BFP#3 ~ 4/15/12, EDD 12/21/12 ~ DD born 12/22/12

Re: Please tell me you're having coffee too.......
I have one cup a day. IMO having a cup of regular is a lot more healthy than drinking decaf. Do you know how many chemicals they have to use to remove the caffeine? Gross. Besides, decaf tastes nasty.
Just keep it under 300 mg a day and you will be fine. FWIW, I had a cup a day with my daughter and she was born perfectly pink and almost 10 lbs.
Drinking some caffeine is fine. Just don't overdo it. I would be drinking coffee if I didn't think it tasted so gross right now.
ETA: Plus if you are only TTC, I don't really see what it matters. I didn't cut out anything (coffee, alcohol, raw fish, etc.) until after I found out I was pregnant. I guess the only thing to be worried about at this point would be possible withdrawals.
My sure South American women continue to drink coffee and Asian women drink tea when they get preggo. Anything in moderation is probably okay. And yes, I am still drink the occasional latte, diet coke and chocolate.
In the very early stages of pregnancy, you and the baby don't share a common blood supply so any coffee you drink for the first few weeks won't have any impact on the baby, drink up. If you're a real caffeine fiend though, you might want to start cutting back, or switching to a brew that has less caffeine in it. A Breakfast Blend will have more in it than a darker coffee (the beans that are roasted longer and are darker have more caffeine burned out of them).
If it makes you feel more confident, I'm normally a very heavy coffee drinker, and I'm down to four - five cups a week with no headaches (knock on wood) There's something to be said about knowing something isn't good for the baby, my mind just kind of took over and said "Ok, we can't have this anymore for a while, just deal with it."
Oh yes, I need my coffee. When I told my OB it was the only thing that would get things moving (wait until you experience pregnancy constipation) he said, "By all means, have a cup of coffee!"
If you're just TTC I don't see why you'd start eliminating anything from your diet at all.