Your least used part

[Cydonian Monk]

Any part that has anything to do with Xenon gas.

[AndrewBCrisp]

But thats the most fun!

Then... because they look funny, and then there's the smell!

[AmpsterMan]

These two parts are my least used in the sense that I have NEVER used them and don't plan on using them. Surprisingly, I use the large radials quite a bit more than most it seems. One of my favorite ways to use them is to attach four of them to a Two Meter fuel tanks with a quadcoupled LV-30.

[Giggleplex777]

The Inline Advanced Stableizer. I have never used it since 0.21.

[The Destroyer]

These two parts are my least used in the sense that I have NEVER used them and don't plan on using them. Surprisingly, I use the large radials quite a bit more than most it seems. One of my favorite ways to use them is to attach four of them to a Two Meter fuel tanks with a quadcoupled LV-30.

Same here. I use the RCS port for little engines on small probes.

[SkyRender]

I'm fairly sure I've never used this thing. Incidentally, I've come to love the small hardpoint for my smallish landers. It's just the right size for sticking a pair of side fuel tanks on them while keeping the lander's form factor nice and compact. Edited October 20, 2013 by SkyRender

[Levelord]

This has consistently been the most useless piece of trash to ever grace the parts menu.

[Brotoro]

I've never used the Mk2 Cockpit... Not that I've got anything against it.

[Cipher29]

Man a lot of hate on the Mk55 engine. They're actually pretty great if you use 4 of them with 4 LV-T30's in a booster stage. You get more thrust and more Isp than the skipper. Not to mention ridiculous gimbal range.

EDIT: Wow, didn't even see this:

-Snip-Surprisingly, I use the large radials quite a bit more than most it seems. One of my favorite ways to use them is to attach four of them to a Two Meter fuel tanks with a quadcoupled LV-30.

I like the way you think sir!

Edited October 20, 2013 by Cipher29

[spikeyhat09]

this

this

this

these three

this

this

and this

[Kasuha]

Parts I literally never used are

QBE

HECS

OKTO

[Sargent890]

I rarely use nosecones or adapters.

[Dooz]

This little piece of junk

http://wiki.kerbalspaceprogram.com/wiki/AV-T1_Winglet

[Sargent890]

These engines are standard on my Mun and Minmus missions. It spares me the weight and space of both a descent and an ascent engine.

[Torham234]

I don't remember to use this: http://wiki.kerbalspaceprogram.com/wiki/Small_Hardpoint

I use them on some of my planes. Useful for the landing gear, if you want to give the craft extra clearance off the ground.

Edit: On topic, I don't think I ever used the AV-T1 Winglet. I do not like how they have a different texture to all the rest of the avionics parts, so they do not "mesh" nicely with the rest of the plane.

Edited October 20, 2013 by Torham234

[Rainbowtrout]

This little piece of junk

http://wiki.kerbalspaceprogram.com/wiki/AV-T1_Winglet

Same here. I saw it in the demo and thought "what is this?!"

[Eric S]

I'm fairly sure I've never used this thing. Incidentally, I've come to love the small hardpoint for my smallish landers. It's just the right size for sticking a pair of side fuel tanks on them while keeping the lander's form factor nice and compact.

Actually, I've used those on a lot of my motherships that drop probes because it detaches from both sides, so I don't wind up carrying unneeded mass on the mothership, and my probe isn't lop sided.

[Brotoro]

Actually, I've used those on a lot of my motherships that drop probes because it detaches from both sides, so I don't wind up carrying unneeded mass on the mothership, and my probe isn't lop sided.

Wait....that engine pylon is a DECOUPLER? Dang...I learn something new every day.

[SpaceSphereOfDeath]

These three parts.

Essentially this, but with the middle size decoupler, I've lost count HOW MANY TIMES THE GAWD DAMN THUNGS WONT WORK, so I use separators instead.

(Yep, Brotoro, it is a decoupler, learnt it the hard way )

[Crush]

and this

Did you check it out in 0.22 career mode? It's not a SAS module anymore. It's now a scientific experiment.

[superm18]

Struts.

...

BAHAHAHA. Sorry, couldn't keep a straight face for long enough.

HA HA HA!! Rolling on the floor laughing!

[FellipeC]

Any part that has anything to do with Xenon gas.

From time to time I try to make a useful probe with Ion propulsion. And fail.

[SuperWeegee4000]

I've got to say the structural pylon and the small hardpoint. The pylon is not fleshed out at all.

[Needles_10]

I've got to say the structural pylon and the small hardpoint. The pylon is not fleshed out at all.

Definitely.

[Merinsan]

Any part that has anything to do with Xenon gas.

I seriously considered ignoring the xenon node in the tech tree even after I got everything else.

But the winner has to be the not rockomax connector. Everytime I try to use it, it looks stupid so I trash it.