As far as major brand oils go, I'd pick Mobil 1. Volvo reccommends 7,500mi oil changes in my S40. I would never do that with a non-synthetic. Have no problem with my full-synthetic of choice, Amsoil....would also be comfortable with Mobil 1 as well.

I don't think it's too early or too late to switch to a good full-synthetic. The S40 got it at 5,200mi and the 240 got it at 231,000mi. Nowadays, Volvo has a detailed protocol for factory break-in of all their engines so special oil/changes are not really needed to condition a new engine. If it's ready to change go to the good stuff.

mormit
1985 245DL 233,000mi
2002 S40 7,800mi

There is continuing debate about how soon to switch to synthetic on a new car. Covettes come with a crankcase full of synthetic... but, it's up to you. Since I think the jury is still out, I would probably go 10K total on dino oil, then switch to synthetic. My 850 got its first Mobil 1 at 85K and my 'new' 240 got it at 110K... I was a late convert. My vehicles see moderate service (50 and 80 mile daily round trips, no too much stop-and-go) so I feel OK about 5K oil change intervals. 10W-30 in each, per Volvo's recommendation.

I've consistently used Mobil 1 10w-30w Fully Synthetic. I also change the oil myself each 5,000 miles. A six pack of M1 is about $23 at Costco.

Also, the trash service in my area is very convenient. They provide me with a container for used oil and bags for the used filter - And, they pick this up with other recyclable items during trash pickup. Before this service existed, I routinely hauled the used oil/filter to Kragen.