Some helpful thoughts...
For primary professions, pick Mining and Herbalism (at level 5). [edit] You gain experience for each node mined or 'herbed', plus they can be pretty good money makers. As of 1/3/2011, you no longer gain XP for mining/herbing until you reach level 10. *shakes fist at Blizzard* [/edit]
For secondary professions, pick Fishing and Cooking (at level 10). You get good experience for the Dailies.
Of course, getting to level 5 is quite a challenge. Visit all the starting zones for Exploration experience as well as the occasional low-level non-combat Quest.
Mining and hunting herbs can be a challenge at level 5 as well as most mobs will be above your level.
Once you reach level 10, you can get about 4 bubbles per day just for doing the two Dailies. That's pretty much a risk-free level every 5 days.
I'm currently looking at Black Dragonflight (4400 Alliance/10600 Horde population) for Ally alt and Tichondrius (16800 Alliance/3900 Horde population) for Horde alt.
If anyone is interested, we could form a guild on these servers (name suggestions?). We wouldn't necessarily quest together but it at least would form a social chat basis for help. Then, once someone fails (kills, is killed, whatever), that person would be promoted to a 'higher' rank and become inactive, and the player could start again.