Job and server to start on?

Hey guys, Been looking at the game and when it went on sale I decided to buy it and now that it's finished installing I'm ready to start playing but cant decide on what server or job to play as.

I'm currently playing on Leviathan because I heard the higher population realms at at the bottom and that was the lowest non legacy server(idk what a legacy server is). I'm also at this point trying out a pugalist>monk because I heard they were cool and will be trying out a lancer>dragoon here shortly. Would any recommend either of these over the other?

There's little reason to choose one DPS over another. They all have their own advantages and disadvantages, and while some jobs may currently be better than others, constant updates mean they will not always be on top. Pick the class that you feel you enjoy more.

That said, I would encourage you to try a tank or healer. As with most MMOs, those two types are in demand, and I find they're a lot of fun.

I've heard that Leviathan is a lowly populated server but I see tons of people on whenever I'm on and at all hours of the day/night.....I would highly recommend finding a Free Company(FC) and/or Linkshell(LS) to play with, they will help you along your way in the game. If you need a friend look me up and check out the server forum on here for a FC or LS

as for the DPS question it depends on your style of play, I like ranged DPS so I play with a Black Mage but am trying out all the other classes also to try them out

Server-wise, Exodus, Balmung, and Sargantas are some of the most populous. I also believe Sargantas has a number of World Firsts, although that information might be dated now. Still, you might consider it if you are planning to pursue end-game content at a hardcore level. Otherwise, Balmung and Gilgamesh are the hotspots for the RP community. BTW, legacy servers are servers with players from the original FFXIV release. Generally, just think of it as a server where players may have up to a 1 year lead on you in levels and items.

Fortunately for classes, monk dps is slated to receive a substantial buff to their primary damage mechanic. Lancer/Dragoon is also scheduled to receive some smaller improvements with their skills. Archer/Bard dps is going to receive a small nerf, specifically removing a substantial cross-class skill they use to increase damage.

As far as dps goes, pugilists and lancers both have very specific combo and skill rotations they use to maximize their dps. Lancers have a little more margin for error compared to pugilists, but their ideal rotations are more complicated than the pugilist. These two classes are also prized for their limitbreak abilities as they do the most damage to bosses. Just be certain to upgrade your weapons as soon as you can.

Archer/Bard plays an unique combination of dps and support. They are the only class that helps recover TP and MP, and they have very reliable silence skills used in end-game content. You won't lack for a party if you're good, but there are admittedly a lot of bards.

There is a great demand for tanks, so you will quickly be picked up by any FC or LS if you choose to play one. Healers are a little more common, but still in high demand.

A lot of job have cross skills from other classes. Monk requires lancer to level 15 and pugilist to level 30. But you can also use skills from marauder up to level 12.
Dragoon is a bit different with marauder to level 15, lancer to level 30, but also uses some pugilist skills.

http://www.ffxivguild.com/ff14-job-requirements-arr/
http://www.ffxivguild.com/ff14-cross-class-skill-guide/