Advantix, but as PPs have said, it needs to be two weekly (monthly for fleas). We stick to monthly, but check our dog daily (it's not hard, he spends his evenings right beside us).

He has had a paralysis tick once in his 12 years, it was scary and expensive - a weekend in the vet clinic and $1K later. I have taken grass ticks off our dog and us from time to time, it isn't hard but you have to be careful. We got caught out with the one that needed the vet - the tick had fallen off but still poisoned him. Luckily I was concerned about his symptoms, even though neither I nor the vet (after shaving) could find the tick. I found a mark on his neck where it must have been.