First recipe without a kit

I just made my first batch with a recipe instead of a kit.  See below* 
I had a couple of questions.  What is the purpose of gypsum and does it 
make a huge difference?  From my brewing books, it gives the water some 
minerals making it heavier and changing the PH levels.  I use city tap, 
but it still has a little "flavor" to it.

Second, for priming, is corn sugar the best or are there other options?

3 lbs dark malt
1 lb Belgium candy
2.5-3lbs Honey
1 oz Cascade
1 oz Fuggles
1 tsp Irish moss
1 package Muntons

I started the honey in the water and brought it to low boil added the 
malt, candy and 1/2 oz Cascade.  I added the other 1/2 Cascade @[EMAIL PROTECTED]
 30 min. 
1/2 Fuggels at 15 min then the other 1/2 Fuggels and Irish moss at 5 
min.  Total cook time about 1 hour 30 with 1 hour boil.  I got a very 
clear brown with a foamy head when I poured it into the primary and 
there was a great malty/hoppy smell.  The starting gravity was 1.05 and 
I could here it chugging along in the closet this morning.

 From what I have read, adding the honey in early and boiling it removes 
most of its flavor and character.  I'm not sure why that would be.  I 
also read an article in Zymurgy talking about the difference the type of 
sugar you use can make.  My whole theory on this one was a mellow dark 
beer pu****ng on the sweet side.  So final question, at what gravity 
should I put in the secondary and what final would/should I expect?
-- 
James

"Filled with mingled cream and amber; I will drain that glass again; 
Such hilarious visions clamber; Through the chamber of my brain; 
Quaintest thoughts, queerest fancies; Come to life and fade away.  What 
care I how time advances?  I am drinking ale today."

~ Edgar Allan Poe