the biggest names out there are obviously fox farms, promix and sunshine mix.. which one you use is really up to you and whatever fits you bill..some people swear by say fox farms while others will say that promix is the best.. i'm sure that most any good soil that you can get that isn't full of time released nutes like miracle grow or scotts, whom i think mg now own, will be fine for your plants..
i also like to cut any soil that i use with about 25% vermiculate or perlite, whichever you can find, for some added aeration and better draining..
alot of people also like to amend their soil with nice organic fertlizers like worm castings, blood and bone meal, seaweed, the list goes on and on.. subcool has an awesome recipe somewhere on here for his own super soil.. its a lil more work to make your own, but than you save money on chemical nutes later on..
and yes, you can use the same soil from seed to weed.. just make sure not to feed and seedling with anykind of chemical ferts for the first two or three weeks of life or you may burn your babies..