Since
theres so much to tell about fire mages and I don't want to spend all
my time and energy on a single post, this guide will be in multiple
parts, going through the general stuff first and ending in some more
advanced tips and tricks.
Yes, you read right. One more part of the PvE guide that I "finished" a week ago or so. I forgot to issue these two things which I'll be going through in this part. Thanks to the guy who whispered me in-game one day asking for this since it was missing from the guide.
So,
this part of the PvE Guide will be going through different races & professions from a mage point of view.
Races
Racials and their benefits have always been one of the biggest questions in WoW since the race change was implemented in 3.2. I'll be going through every race, starting from the Horde races and explaining how/if the racials for the race benefit mages in PvE at all. Keep in mind that the difference between the worst and the best racial is around 800 DPS in BiS gear so if you're not really into minmaxing this part of the guide probably isn't for you. I'm going to be starting with Alliance races.

For Humans, the racial that could benefit mages in PvE is
Every Man For Himself, and it is, to say the least, very situational. There isn't a single encounter in DS where you could use it. So generally Human is a pretty bad choice for PvE mage race.

For Dwarves, there's also only one even slightly beneficial PvE racial, which is
Stoneform. In the bigger scheme 10% damage reduction won't do a lot and the rest of the effect is useless so once again, a pretty bad choice for PvE.
Night Elves... Again, no good racials for PvE.
Shadowmeld could maybe be useful (can't imagine any situation where though) but yeah, no.

Gnomes have one mildly beneficial racial for fire mages:
Expansive Mind. However fire mages don't really have mana problems and don't benefit from a bigger mana pool so gnomes aren't a good choice either. For arcane mages Gnome is the best choice out of the alliance races though.

The draenei racial
Heroic Presence is one of the best choices for Alliance mages, requiring you only to get 16% of hit from gear. The draenei racial is usually really good in the first tiers of an expansion due to lower amount of stats in gear. Also
Gift of the Naaru can be a situationally useful self-heal.

The worgen racial
Viciousness is generally speaking the best racial for PvE fire currently out of the alliance races. It beats the draenei racial with current BiS items due to the fact that you aren't really reforging any crit to hit anyway and crit happens to be the best stat for mages. So with draenei racial your benefit will be mostly some more mastery/haste but with the worgen racial you'll always gain 1% of your best secondary stat, crit. Also the sprint racial,
Darkflight, can be useful but there's less situations where it's useful for mages due to blink & ability to dps pretty well while moving.
Conclusion for the Alliance races: Worgen > Draenei > Gnome > Human = Dwarf = Night Elf
Now onto the Horde races. Skipping tauren for obvious reasons :).

Orc is a fairly good choice for PvE with it's
Blood Fury racial. At lvl 85 it grants you 1302 spell power for 15 seconds with a 2 minute cooldown. Because Combustion doesn't directly benefit from spell power this race is worse than some other choices though.

Undead racials are fairly useless for PvE.
Will of the Forsaken could be useful in some situations but in the current tier of raiding no such situations exist. Generally considered the worst choice for a Horde PvE mage.

The Troll racial,
Berserking, is currently the strongest choice for PvE Fire. Unlike the tooltip would let you understand, you gain the benefit as haste rating, not just as casting/attack speed, which means that with Berserking up you can reach extra ticks for DoTs, for example Combustion, which are a big increase in DPS. Also the racial
Beast Slaying can be really insane on some bosses, examples of bosses like this in this expansion are Chimaeron in T11 & Beth'tilac in T12.

The only Blood Elf racial that can be beneficial in PvE is
Arcane Torrent. However due to mages not really having any big mana problems as fire, the benefit from it is minimal in the current tier.
Goblins are also a pretty good choice for Horde PvE mages.
Time is Money is generally speaking a pretty good racial, in BiS gear the difference between being a Troll or a Goblin is around 350 dps to the favor of being a Troll. Also the
Rocket Jump racial can be useful at times but again Blink makes it a bit less useful for mages. Using
Rocket Barrage is a dps loss and thus not beneficial at all.
Conclusion for the Horde races: Troll > Goblin > Orc > Blood Elf > Undead
Professions
For the professions, I'm just going to explain the few interesting ones due to something special with them and then list all the middle-ground professions with the same benefits.
You should never have Herbalism/Mining/Skinning if you're minmaxing on your mage because those professions are miles behind the others in terms of dps increase.
Blacksmithing is the strongest profession for mages since 4.3 and the addition of the 50 stat epic gems. Blacksmithing gives you two extra gem slots in which you can put two 50 intellect gems, thus giving you
100 extra Intellect. This is the biggest bonus you can currently get out of a profession.
Out of the current professions, tailoring is the second strongest choice. Tailoring gives you a special
cloak enchant, Lightweave, which outweights most of the other professions.
Jewelcrafting has usually been the best profession alongside tailoring, giving you one more intellect than the other professions (81), but with the addition of Epic gems it is now the worst non-gathering profession available because Blizzard hasn't fixed the JC only gems to give more intellect. Jewelcrafting now provides you with only
51 extra intellect. I doubt they will fix this during Cataclysm which is a huge shame, but in MoP, with no epic gems, JC will most likely be the best profession again alongside tailoring.
Although Engineering is arguably the most interesting and unique profession in the game, it's
PvE benefits are generally bad for fire mages.
Alchemy/Inscription/Leatherworking/Enchanting all give you
80 extra intellect and are thus the best choices for PvE after Tailoring & Blacksmithing.
This should finally sum this whole Mage 4.3.3 PvE guide up, hopefully it was helpful to at least some and the usual stuff. If you haven't, be sure to check the previous parts! If you still feel there's something missing from my whole guide, please leave me a comment or poke me in-game on EU Jaedenar and I'll do my best to add it!