I think it is personal preference as well and depends greatly on the rest of the gear being worn. I can't comment on PvP because I refuse to engage in it under the current system and haven't done so since comming back 2 years ago. For PvM I'll chime in...
HML (Hit Mana Leech) I rank #1 above everything. Rarely do I use a weapon without it. You run out of mana on pretty much any template and your out of the game so to speak. You can't heal and you can't buff spells. Whammy is probably the only template that could successfully get away without having HML on their weapons.
SSI (Swing Speed Increase) #2 Nothing is more important to damage output than speed. In most cases the faster weapon will out perform the harder hitting weapon. Just like in boxing "Speed kills Power".
HLD (Hit Lower Defense) Ranks #3 in my book. The high end monsters are sometimes very difficult to hit and this is where HLD can pay off big dividends. I noticed this mostly on Prince Paroxysmus..without my Mace and Shield Glasses (30 HLD) I constantly missed. Especially when playing templates that rely heavily on life leech. Hitting or missing means life or death against the higher tier monsters.
The remaining big properties depend heavily on template being played and are more of a personal preference so it's difficult to rank them:
HLA (Hit Lower Attack) I would definitely want on a melee character but not Top 5 choice for my archer.
Damage Increase - I know this sounds crazy but I'll pass on this property as you can hit 100 DI with the right gear and equipment so my perfect weapon or bow wouldn't have this property on it. HCI and DCI you can all max out on via proper gear so those aren't properties I would look for on weapons either.
I'm not sure the about the limitations on intensities that are going to be allowed on properties for imbueing and unraveling. I do believe they said 5 Mods maximum. So my dream melee as of today would probably be something along the lines of:
Twinking Scimitar:
30%-50% Hit Lightning
30%-50 % Hit Mana Leech
30%-50% Hot lower Defense
30%-50% Hit Lower Attack
30%-50 % Swing Speed Increase
default 6 DCI
One handed and carry alot of refresh potions.
Magical Shortbow:
30%-50% Hit Lightning
30%-50 % Hit Mana Leech
30%-50% Hot lower Defense
30%-50 % Swing Speed Increase
Balanced
Where can I get one?
![Tongue :P](http://www.scriptuo.com/Smileys/yarex2/tongue.gif)