30 points in Wilderness Survival is a must unless you will never be in melee. Zergs take the 30% dmg reduction, for roaming take the pets take 3 condi's every 10 seconds. From there your options open up quite a bit.
Pets:
Jaguar is your best DPS pet (though all cats are good for dps, dont use birds), while canines have some of the overall best Utility. Solid CC, good F2's, somewhat tanky and somewhat good dps. Fern Hound has an excellent 5 target AoE heal, while there is also a wolf with a Fear and a hound with an Immob. If you will mostly be in Zergs take a look at some of the tankiest pets instead. Also, check out the Drakes. Their ability chain has a blast finisher and their F2's have some good AoE.
Personally I only use Cats (roaming w/BM build), Wolves, and Drakes. Though I've been considering going tankier (like bears) for full blown zergs.
Tagging:
Piercing Arrows and the Greatsword will do you the most good for tagging people in zergs.
Roaming:
Beast Mastery builds (30 in BM and 30 in Wild Surv) roam very very well. The Jaguar with 30 BM and with Sick Em does some pretty impressive dmg. Slap on some healing gear and you have a bunker build that still deals really solid dps. If ever using healing gear use the Fern Hound.
Frontline Support:
You can build just about any way you like excepting 30 Wild Surv (which really is just about mandatory for any frontline/roaming fighting as a Ranger). Slap on some Toughness and use Axe OH with binding roots Elite. Run into front line and pop your number 5 Axe, elite before/after pending zerg, and you will seriously mess up their day.