I recently did some railings of my own and used a product from
http://www.deckorators.com/ for the balisters. I got the "Classic" in
powder coated black in the 3/4" x 36" length. They come 10 to a box at
approximately $26.95 to a box. For other applications, they also come in
24" and 32" lengths, as well as other colors. They also sell easily used
brackets for atttaching your rails to your posts. I seem to remember I used
a spacing distance of 3 3/4" on center for the balisters.

My posts are 4 x 4 cedar and the rails are 1 1/2" x 4" cypress. I treated
the cypress with cedar toned Penofin exterior oil finish, but I've also used
Behr Cedar Waterproofing Wood Finish from Home Depot. I suspect the Behr is
a bit better for preventing mildew in the cypress. There is a supplemental
filler attached to the bottom of the lower rail. I used this to get about
2" greater height on the railings and keep my minimum 3" space at the
bottom.

For the gate, I used a large mortise and tenon and some left over 24"
balisters from another job. Being unable to find any latching hardware that
wasn't primitive and borderline inoperative, I simply used a doorknob set
with the handle design shown in the second photo. It works well and I just
give it a shot of lube now and then.

The strange beveled boards you see attached to the posts are the result of
my cats finding the posts to be great scratching sites for maintaining their
claws. I just attached some cedar fencing material and let them shred that
instead of my posts. We're also extremely happy they prefer that to our
furniture inside the house.

I hope this helps,

Wade