I remember a few years back (from elementary school to high school), I was quite obsessed with mechanical pencils (there is something magical about the simplicity and efficiency of the clicking mechanism). It's no longer the star of my stash, thanks to my hands of salamander (pencil writing get smeared way too easily), forgetfulness (in my case, erasers disappear like hair ties and bobby pins) and the distraction by fountain pens. Anyway, I do have four of them so let's take them out for some sunbathing and blab about them for a bit!
Pentel Graph Gear 500 Drafting Pencil 0.7mm - I found it on clearance at Target for $1.49 (down from 5) so I bought it on a whim (turns out that I actually need a pencil that very same day!)
It has a tough metal sleep with a heavy ribbed and textured sleeve, which adds a nice bit of weight to the otherwise light pen. It's rather comfortable to hold and I think it looks quite attractive for the price. I use Pentel HB lead with it and serious have no clue what to say about the writing experience...
Staedtler Mars Technico 2mm lead holder (regular retail at $9, I used a 50% off coupon in Michaels) - Heavier body and a more scratch-proof plastic. The 2H lead leaves a hard and faint line, which is great for drafting and pencil sketching. There is a detachable pointer at the back but it's not very user friendly as it takes several back and forth trips (the thing wouldn't sharpen unless the lead is advanced a few mm beforehand and the clicker doesn't advance the lead unless the pointer is attached to the back...)
Sakura 127 0.7mm (comes with the Pigma Sensei/Pigma Micron set) - Nothing special beside the black plastic scratches quite easily. It does get the job done and it hasn't fallen apart.
Tizo 天卓"Card-filler" pencils (1.5 Yuan in Chinese stationery store and online, which is around $0.25 US) - This flat lead-holder is specifically designed for speedy form-filling in one or two swipes. It's somewhat light weight but I have one that lasted me for years (beside the golden paint "Specifically for computerized exams" that get rubbed off over time). There are four shades available (black, blue, gray and brown) but I only saw two in that store I visited.
The Tizo refill is also readily available in Chinese stationery stores at 1.5 yuans for 6 leads (the same price as the pencil). The lid is not well-shut so I usually tape it over when I buy new ones. Overall: Beside the Tizo one (which I highly recommend) , I don't have much to say about the rest...Now I just wish they come in prettier colors.
Short writing sample of the four pencils (which already got smeared a bit when I touched the paper)