Hi dts,
If you want to be super healthy, Patrick Holford has a book called "Optimum Nutrition Before, After and During Pregnancy" which outlines what you should/should not eat while ttc, including what vitamin supplements you should take.
Some people find him to be a bit extreme in his thinking (absolutely no caffeine, little to no sugar in favour of natural sweetners, no processed foods, no white/refined flours, no fizzy drinks, dilute fruit juices 50/50 with water..) but I try to follow his eating plans as far as I can, while regularly falling off the wagon without feeling too bad about it (he also has tons of books on low GL eating, healthy eating, nutrition etc
www.patrickholford.com/).
Generally he recommends taking some sort of omega supplement, a multi-vit/mineral and a vitamin C supplement (in addition to your muli-vit). For pregnancy/ttc he also recommends vit B supplements, folic acid and a few other things.
I have the book tucked away somewhere and can check it up for you if you'd like.