I use Valvoline MaxLife Synthetic Blend 10w30 in both of my Honda Accords. OEM spec is 5w30 and the manual says 10w30 is OK if your climate never gets below 20*F. I live in Mississippi, and it rarely gets below 20. Every now and then it does though. But I use the 10w30 all year round and I've never had any issues. The 2000 has 130k and change. The 95 has 120k and change. The mustang has around 180k, but it sits in my dad's garage an hour away from my house. he drives it every now and then. We use 10w40 in it and it doesn't leak a drop either.
I plan on selling the 95 sometime soon. The V6 in it was Hondas first attempt at a V6 in an accord, and the engine is known for leaking in various places. It does have a few slow leaks, but nothing to worry me terribly. I plan on taking the 2000 Accord to 500k. Once I hit 250 k or so I may contemplate switching to 10w40 if I see any leaks. But if I still have no leaks, I'm sticking with 10w30. One of my mottos has always been "If it aint broke, don't fix it."