Well if you're looking to start
AoS, you cannot go wrong by checking out the Start Collecting box sets and figuring out what you like the look of.
Find them here
If you rank Orcs (Orruks now
) first and were looking to go for a more Elite army then the Ironjawz are pretty cool. Orcs who have been fighting and winning for so long their smallest members are the
Brutes and other Greenskins flock to as they know when the Ironjawz go to war it'll always be a good fight.
Ironjawz just got some awesome new Alliegience abilities with GHB2017 as well but they are pretty much a pure melee army if you don't take allies.
In terms of Humans, there aren't really any new factions though Freeguild are still about (but no Start Collecting box at the moment.) Chaos "humans" are present with the Bloodbound/Blades of Khorne if you were looking there. (again very melee focused though)
The Duardin have two new factions in the Fyreslayers and the Kharadron Overlords and still have the Dispossessed and Ironweld Arsenal (which together make up the bulk of the old line).
The Fyreslayers would be the cheapest with a Start Collecting box that is now quite cheap by comparison to it's contents ~3 months ago, but they probably have less overall selection. They do have some shooty and melee units though and the Magmadroths are really cool.
The Kharadron Overlords don't have a start collecting box but their miniatures are amazing and the overall theme of Steam-punk (really Aether Gold-punk) Sky Pirate Dwarves is awesome.Again easy to run as very shooty or a mix, very versatile these guys.