what are the best enchantments to you?

[Run, Just Run]

I have the ability to buy a +5 weapon as a 2-handed fighter and am not sure what enchantments to get. Currently I have speed and an ability called impact which is a +1 enchantment which increases the damage step by 1 size category for 3d6 from the original 2d6 but I'm curious as to what you think of as the best enchantments. Thanks.

[XMorsX]

For high critical threat weapons I would say +4 keen or +1 keen brilliant energy with greater magic weapon cast on it. Otherwise a straight +5 or a +1 brilliant energy corrosive with greater magic weapon cast on ot work great.

It depends though. For some builds Agile or Guided enchantments are an absolute priority. A barbarian or generally anyone with the rage class feature certainly want the furious enchantment asap. Holy (or unholy) is a must have if you don't take only enchantment bonuses for bypassing the aligment DRs. Any intimidator will want cruel and ominous, and courageous is excellent if you can have greater magic weapon cast on your weapon. Also bear in mind that brilliant energy, while a very powerful ability, is equivalent to a +3 bonus, very expensive to save for as a result.

[Mapleswitch]

Human Bane (+1 bonus cost: +2 to hit and damage and +2d6 damage vs. humans) Humans are the most common enemy in the games I play.

[MatthewN]

Speed and Impact are good choices if you don't have reliable access to haste from a party member.

Brilliant Energy is a trap. It's definitely not worth the +4 bonus.

Holy is an excellent choice. Most of the things you fight will be evil.

[Lord_Malkov]

Depends on what you play. Franlky I dislike ominous and impact which were cited here

Ominous adds to intimidate and can intimidate for free on a crit but if you are a build that uses intimidate you probably have some way to use it easily (performance, intimidating glare dreadful carnage etc.) There are better ways to get intimidate bonuses without paying the hugr cost to get it on a weapon.

If you are a barbarian I would say that +3 furious/ courageous is the way to go. Or +2 furious courageous keen if you don't have imp. Crit.

Furious treats your enhancement bonus as 2 higher when raging
Courageous adds half your enhancement bonus to any morale bonus, which means all rage bonuses and superstition.

[Kayland]

Whatever sounds most enjoyable from a roleplaying perspective for any given character.

[Drejk]

Best enchantment? Dominate monster.

Spoiler:

In Pathfinder/D&D 3+ Enchantment is school of mental manipulation and control. What you are looking for are weapon properties/enhancement.

Sorry for nitpicking. Carry on.

[Run, Just Run]

thanks for the advice

[master_marshmallow]

Impact is actually a +2 enchantment I believe.
What materials are available?
In 3.5 there is Collision which adds +5 to the damage every hit, period, for a +2 enchantment. It was remade the exact same way in Dreamscarred's Psionics expansions for Pathfinder.
Keen is okay, at later levels when I have the feats to spare on taking improved critical I prefer to have a feat spent on that to get more out of my weapon.

[Run, Just Run]

only pathfinder stuff by paizo sadly.