Sneaking Potion

This is not correct, just tested it on some that I'd made. You can drink this while stealthed without breaking it.

The following items give the following bonuses to stealth. 5 points means that you will be as difficult to detect in stealth as a character one level higher. (So if you are a level 22 character and have 15 stealth bonus points, you will be as difficult to detect as a level 25 character with none.)

Stealth of the Stalker - 8 stealth points, lasts 5 minutes.
http://www.wowhead.com/?item=31450

Sneaking Potion - 30 stealth points, lasts 1 minute.
http://www.wowhead.com/?item=22826

Booths of Displacement - 8 stealth points
http://www.wowhead.com/?item=23073

Darkmantle Boots - 8 stealth points
http://www.wowhead.com/?item=22003

Silent-Strider Kneeboots - 5 stealth points
http://www.wowhead.com/?item=27467

The Master's Treads - 5 stealth points
http://www.wowhead.com/?item=31288

Whisperwalk Boots - 5 stealth points (Rogues only).
http://www.wowhead.com/?item=20255

Nightscape Boots - 5 stealth points
http://www.wowhead.com/?item=8197

Figurine - Nightseye Panther - 5 stealth points
http://www.wowhead.com/?item=24128

Enchanting your cloak with Stealth - 5 stealth points
http://www.wowhead.com/?item=20734

Figurine - Black Pearl Panther - 3 stealth points
http://www.wowhead.com/?item=21758

Each point in the rogue talent "Master of Deception" is worth 3 stealth points.
http://www.wowhead.com/?search=master+of+deception

Each point in the druid talent "Feral Instinct" is worth 5 stealth points.
http://www.wowhead.com/?search=feral+instinct

Lastly, being a Night Elf, with the racial passive Shadowmeld, is worth 5 points.
http://www.wowhead.com/?spell=20580

Ever see a tauren stalk a python? Of course you haven't, that's because tauren are so adept at blending into their surroundings.