If your going to buy a longboard, your going to want to buy one that your going to be able to use for a long time, because I guarantee you that you will get addicted.
First things first-
-Board shape
your probably going to want something symmetrical. Alot of people tend to get pintails as there first board, but trust me, your going to want to replace it after the first few months. The plus side of a symmetrical board is that riding switch, regular, or any way you flip or spin the board, you will always be facing the right way.
Board length-
I would look at something between 38 and 42 inches. In my opinion 40 is the perfect length. This length will give you enough length to have stable footing as well as having the ability to cross step a little in the future.
With board length and shape in mind you have a few options.
You can get an earthwing supermodel which is a great board and will last you almost forever.
Loaded Dervishes are also good, but a little on the expensive side. They are great all around and are slightly better for cruising then the supermodel.
Lastly you have the BC Eel. It has a long build time, but is in my opinion the best board of all of these.
Trucks-
basically 4 affordable options for what you want: paris 180, gullwing charger, randal 180, and bear grizzleys.
Paris trucks are by far the best for craving no question. A little less stable at speed.
Alot of people hate on gullwings, but chargers are great all around trucks.. Very carvy. alright at speed.
Randals are considered the end all be all all around truck. They will do well at anything.
Bears are conisdered great for downhill and not so much for carving.
Wheels-
I would buy any 70mm 80a-83a wheel: abec 11 zig zags, metro motions, and otang stimulus are good. Metro motions are my favorite. Theres a lot of hype for stims but they wear out quick.
for bearings just get bones reds.
SPARK NOTES:
get an EW supermodel, dervish, or BC eel with randal 180 trucks and either abec 11 zigs or Metro motions