I have a fair amount of grease in the shop... marine bearing grease is more than you would ever want for a bicycle's bottom bracket or hubs and provides excellent washout protection and synthetic is even better if you have to deal with colder temperatures.

Pick up some Mobil 1 synthetic... a pound is around $8.99 (U.S.) and you will be good to go for a long time.

Bicycle hubs, bottom brackets, and other bearing assemblies do not have to withstand the heat and pressures that automotive grease does but they are exposed to the elements so a marine grade grease is the best option.