What is your favorite brand fly reel, fly rod, terminal gear, etc... and why?
Fly Rod: I'm going with my home state, and choosing St. Croix's Legend Ultra. I have a 7'6" 2-weight, and a 9' 7-weight. I absolutely adore both. The Legend Ultra is a fast rod, and really casts the line. I overline the 2-weight with 3-weight double taper, but it still casts pretty fast. I once had a 8'6" 5-weight St. Croix Avid, which was a nice rod, but a little mushy for me.
Fly Line: Rio or Orvis Wonderline Advantage. Rio does not seem to have as much coil memory, but Wonderline is extremely slippery and low maintenance. Right now, I have Rio for both 3(2) and 7-weight's. The 3-weight is double taper floating and is great for casting light dry flies. It works well for nymphs, but a little light for streamers. Furled leaders help with heavier flies. The 7-weight is Weight forward floating. The weight forward works great for heavier flies, hence the 7-weight. This is a situation where furled leaders really help with lighter flies.
Leaders: See my site -- Furled leaders.
Tippet: Orvis Super Strong. Strong and supple. Well priced.
Reel: Ross Reels -- Rhythm 1, and 3.5. I had an Orvis Battenkill Bar Stock III, and a St. Croix Bar Stock Legend 3/4. Now, before I go any further, the reel is the least important item for spring creek fly fishing. For salmon and steelhead? That's a different situation. What is important is to get a reel with light startup drag, to protect the tippet from hard takes. The Orvis BBS and St. Croix Legend were fine reels, but I wanted a larger arbor for my 7-weight. I purchased the Ross Rhythm 3.5, and liked it so much, I needlessly purchased a Ross Rhythm 1 for my 2-weight. Awesome reels that are hardy, light, and have the softest startup drag of any I tried. The 3.5 has a heart that can stop a truck. Try one.