Mages are great they have those lovely portals to all the major cities and we're all dead jealous, druids and death knights get a taste too with their class portals to Moonglade and Ebon Hold respectively. But the rest of us just have to rely on our mounts, flight masters and boats or zeppelins (depending on our faction) or do we?
I'll admit that many of these portals are level dependant or rely on quest chains being completed, but to the savvy (or lazy?) level 85 most if not all options should be available or can be had quickly if they're not. I apologise in advance for the slight Alliance bias but I don't yet have a level 85 Horde. /hangs head in shame.
Firstly from Stormwind and Orgrimmar there are portals to all the Cataclysm zones including Tol Barad all have to be opened by questing and means that they are level dependant. Most of these zones have a portal back to Stormwind /Orgrimmar too which is cool and maybe sometime soon we'll end up with an Uldum portal although Vash'jir would be troublesome because of the way the portal phases you into your current phase questing base.
Shattrath and Dalaran
Heading to Shattrath and Dalaran there are portals to Stormwind and Orgrimmar but sadly these are a one way trip deal only. Shattrath and Dalaran also have a link to the Caverns of Time making either city an alternative hearth point if you raid Dragon Soul. Instead of a portal though you need to speak to NPCs, In Shattrath use Zephyr, found in the World's End Tavern in Shattrath's Lower City, once honoured with the Keepers of Time and in Dalaran you need to speak with Zidormi (or use the portal behind her) and no reputation requirements exist :
Dalaran also has two portals to Wintergrasp, each one being faction specific and it is only available if your faction controls Wintergrasp. It is located in the Silver Enclave (Alliance) or the Sunreaver's Sanctuary (Horde):
Besides the flying taxi/zeppelin/boats that link our major cities, there is also the Deeprun Tram that links Stormwind and Ironforge:
Darnassus and Exodar which I wrote about way back when
Silvermoon and The Undercity
Hellfire Peninsula side there is now a portal back to Stormwind / Orgrimmar, I don't know when this got added but the 2 things I know are that it wasn't a working portal in TBC but it IS now!:
Un'Goro Crater and Sholazar Basin. These are activated by completing a quest chain (only 8 quests) beginning with the Avatar of Freya. The starter quest is The Lifewarden's Wrath and shouldn't take long to complete and is well worth the effort if you're stuck in Northrend and wanting to get back to Southern Kalimdor:
Wintergrasp, you can port there from Dalaran and then fly manually the short distance to the waygate in Sholazar Basin. There is also a convenient return to Dalaran from Wintergrasp meaning you can use this as a shortcut back to Dalaran too:
There are other tricks too. If you stuck in Darnassus and want to get back to Stormwind you could use the boat but if the Darkmoon Faire is in town speak to one of their representatives who will port you to Goldshire or just outside Thunder Bluff for a small, level dependant fee. Along with a host of other trinkets, tabard's and doodads to fling you around the world of Azeroth but the ones here are all free or very cheap to use.
Now you are armed with this information you can now use this to help speed your travel around Azeroth! Needing to go to Arathi Highlands for some archaeology? You could fly from Stormwind to Refuge Pointe which takes an age. Alternatively you could portal from Stormwind to Twilight Highlands and either taxi from there or fly manually. Doing the Winterspring Frostsaber grind? You could grab the boat from Stormwind too Darnassus and fly from there OR you could take the portal to Mount Hyjal and fly manually to Winterspring which is a very short hop or take the taxi if you're feeling lazy, although that does take a weird route, it is still much quicker than the boat option.
So if you're on a hole with a hearthstone on CD (or in the bank!) get creative!