Now lubricate with your favorite lubricant. Lubricant choice always seem to be somewhat preferential. Lots of people find one lube that works for them and they just stick with it. It's hard to try out multiple lubricants and get a thoroughly accurate comparison throughout all types of skating conditions. In the end, it doesn't make a huge difference unless you're into serious racing.
Most people end up using grease or oil.
It is very helpful to have a little hypodermic style oiler with a long needle to let you put the oil right where you want it. Grease works well because after a while most of it gets shoved out of contact with the balls and only a little bit smears onto the workings. However, newly greased bearings, will take a while to expel any extra grease and move the rest out of the way. Some brands also come in a very handy hypodermic-style dispenser which is perfect for putting a drop exactly where you want it. Overlubing will not only waste your lube, but you'll also make the bearings more sticky and more prone to attracting dust and grime, which is exactly what you don't want.