The best leveling guide possible we are using the ultimate control toon - the Priest. It's pretty much the standard line that Hunters can level solo faster than any other class. You made arguments for lots of other classes and builds, but when it comes to raw killing power and low downtime it's just really hard to beat a BM hunter for fast leveling. No wonder almost everyone who has done a leveling guide has used a Hunter to do the speed run.
   But we have done something different, we still use a Hunter to test routes and do the final speeds run for time, which make sure that anyone could do everything in the guide with relative ease with any classes. That means everything from begin ners and nubs to complete pros; from BM Hunters to Warriors and Priests.
Even we recommend you run in a party, that's not always possible, so we wanted to make build our guide so that you can run through from 1-70 no matter if you're by yourself or have an entire guild full of buddies. That's to say, it has to be able to work for anybody in any class.
It would be hard to argue that Priests can have a tough time with leveling solo. They don't have a whole lot of firepower, are very squishy, have no AOE and can only crowd control undead which means that they pretty much have to try to force mobs into 1 on 1 match-ups. As usual a bad pull ends up in a bubble, scream and run.
While we're jamming through on Hunter, we ensure that we didn't put anything in the guide that anyone would have major problems with. When it comes to leveling solo as a Priest, we asked our good buddy Lawbringer to bring a Priest through the guide segments as we completed them and since we're almost to 70 we thought it would be good to report some of the interesting tidbits he has uncovered.
When leveling, you know about playing a Priest, you can toss out everything you think. When you hit 60, start collecting "of the invoker" gear. The high intellect, spell damage and critical strike will really speed up your kills. We know it's tempting to opt for spirit, but you are killing, not healing. It for sure is nice to have back to back crits of 1700+ from mind blast and shadow word death from all that extra spell damage, crit rate and the shadow power and misery talents. 3,500 damages are pretty dominating for any class in two seconds.
By using spirit tap and blackout, you reduce your downtime and give you a blackout or two in almost every fight. 95% of the time mobs will never burn through you bubble, meaning you get hit very seldom. Blackouts will proc quite a bit, and spirit tap gives you enough mana regeneration to make it through about 10 mobs before you have to drink.
For the sake of leveling fishing and cooking, the extra 23 spell damage from poached bluefish makes a difference you can really notice in every fight. That's also why the invoker gear can be a make or break selection when running solo in shadow form. Invoker gear and bluefish can give you +350 bonus damage before level 65 which isn't too bad considering we are only talking about stuff you can grab from the AH and quest rewards - just greens in other words (remember it has to be something you can do solo, so don't laugh if you're comparing that to instance drop gear).
 You should keep in mind that everything in TBC is going to be instantly obsolete anyway. More than likely those who have spent months getting all that purple gear will be replacing much of it with greens from Northrend, so don't kill you getting T5 now.