A Resto shaman is a better healer then an Elemental, if you cannot keep the tank up with 4x Elemental.

I'd personally try for all shaman's are elemental, as you have very good offense and enough healing for most content.
In instances, 4x Healing Stream Totem is powerful against a lot of trash. Staggered Stoneclaw totems can be useful, but with a pally they're your Stoneclaw.

Lesser Healing Wave is inefficient, but fast and a quick emergency heal.
Healing Wave is a large heal, especially coming from four shaman's at once.

Resto adds Mana Tide, more efficient heals and earth shield.
Definitely nice abilities.
If you can get by with 4x Elemental, I believe Elemental heals better then Resto nukes.
If you find elemental is not enough healing, go with 1x Resto and see if that works.

Incidentally for leveling, I was using the Kopp outland guide and like that a lot.
His new pricing is pretty sucky, so I went with extremeleveling for questing in Wrath, as one purchase is good for all future updates.

Kopp's older guides (1-60 and 60-70) are available as torrents on www.piratebay.org if you want to try them out.
But if you like them, I'd recommend an actual purchase, just because someone took the time to make them; up to you though.