What I use:
Originally from my blog.
Sketching/Drawing
My current favorite pencil is the Ohto Promecha SP-507P. I pretty much use mechanical pencils only. I don't remember the last time I actually used a traditional wooden pencil. I don't leave home without this pencil, seriously. Loaded with 0.7mm, 2B hardness lead, this has been my primary sketching tool for the last 5 months or so. It's a good quality, all metal (aluminum I think), balanced pencil. Surprisingly light compared to a lot of other aluminum mechanical pencils Ive tried. This one was acquired at the cost of ~580 yen from the Tokyu Hands store in Shinjuku, Tokyo, but I've also seen it carried at Kinokuniya Bookstores and other japanese stores that sell stationary for around seven dollars. The big brother to this pencil is the super customizable Ohto Super Promecha PM-1500. This is the only pencil I've seen that comes with an instruction manual. It's too much pencil for me.
When I decide to sketch in pen I use fine Pentel R.S.V.P. pens. My fashion drawings like this are usually drawn with these pens. They work great for me because they are cheap, easy to find in stores and come in a few different colors. Losing your favorite drawing tool is the worst thing ever. If you use stuff that's cheap and easy to find, it's not so bad.
For erasing I use the two erasers that pretty much everyone else uses: the Design Kneaded Eraser and the Staedlter Mars Plastic Eraser. Both of these are easy to find at most art/craft stores like Michaels, Aaron Bros, ect. If you don't have these, you need to get them...now.
Inking
I'll admit, I'm not really fond of inking my own work, It never seems to feel right. When I do ink my drawings I usually use Copic Multiliners and Tachikawa School G-Pens.