Congratulations on hitting 80!
1. There is no spellpower number to shoot for - the more the better. Additionally, to reduce your GCD to 1 second you'd need approximately 1640 haste rating at level 80, so I wouldn't worry about capping it. As always, it is about maintaining a good balance between your key stats.
2. Your basic gemming should be:
Meta -
Chaotic Skyflare Diamond Note that you need two blue gems equipped to activate it. Use
Purified Dreadstone x2 to achieve this.
Red socket - Easy.
Runed Cardinal Ruby Yellow/Blue sockets - These change depending on your overall gearing. If the socket bonus isn't worth it and you are capped on hit rating and have your two blue gems for your meta, then socket a red for pure spellpower. Since your hit rating is very low currently, I'd suggest gemming for hit in your yellow sockets for now as that will be your biggest dps boost until you get more passive hit rating. Later on, your yellows can be filled with
Reckless Ametrine if you need the socket bonus, or just drop in a pure spellpower red gem. Similarly, if you need the socket bonus then put the
Purified Dreadstone in a blue slot, otherwise just a pure spellpower red gem instead.
3. Databases are your friend, so use them to do some queries and you'll find exactly what you need. Here is a
list of cloth items from the normal dungeons. And here is a
list of cloth gear from the heroic dungeons. I included Trial of the Champion in addition to HoR, PoS, and FoS because it has epic drops that would be of benefit to you, such as
this trinket. Here is a
list of crafted cloth gear. You can do similar searches for weapons, offhands, trinkets, etc.
Raise your skill level in your professions. This will allow you to put
this enchant on your rings,
this on your cloak, and
this on your legs.
Good luck!
Edited, Jan 29th 2010 1:52pm by CountFenris