another noob question

I know what a 40/40 wand/focus set is.
What is a 40/20/20 staff?
And why is it better or worse than the 40/40 set?

Search to the rescue.

[Source]

The way it differs from a 40/40 wand+focus set is you give up a percentage of recharge (either the Memory wrap or "Forget Me Not") for the enchanting duration (which can be crucial in some builds).

Really?
I find that rather unexpected,
I know some people really crunch the numbers to a dps,
but if something works 20% of the time, then it doesn't work 4/5 times
and IMHO you can count on not counting on it... Especially in a hard fight.

Admittedly I'm still pretty much a noob, but the only thing I look
at for an Artifact or Staff is the Energy boost.

In general PvE you can usually get away with any old thing or whatever you prefer. The strict weapon sets that provide such casting enhancements are usually staples in solo farming or speed clear builds where, yeah, DPS and super efficiency are important. In such cases, energy management is usually built in to the bar, in favor of HSR/HCT which, when they do go off, can make things a lot easier -- especially on big spells with long recharges or cast times.

As for the enchanting duration, that can literally make or break maintained invulnerability.

There are similar points to be made for the use of such weapons in PvP, just with different applications.

Keep in mind that a 40/40 set doesn't really give you a 40% chance of getting HSR or HCT.
Details here -> http://wiki.guildwars.com/wiki/40/40

most people choose hsrc or hct over energy because energy may help you a little bit to begin with but if you're running out of 40 energy, you'll run out of 50 energy. on the other hand having something recharge quicker, or something with a big cast time(1.5 secs or more to me) cast in 1/2 the time makes a big difference. regardless, when people do run out of energy, you take a high energy set with "live for today" and "sieze the day" inscripts, and switch to the reserved energy to cast a spell, then promptly switch back to a normal set to maintain the 4 pips of regen.

My own bias would still be if an 8 staff took me to say 38 but a 10 Latern to 40; well thats another 5pt spell open and available; but perhaps I have been too dismissive of the staffs; viewing the 20% of the time buffs as basically worthless.

Lots to think about thanks for the advise. BB.