Bring absolutely everything beauty-wise you can't do without. Finding replacement products here is often impossible and usually expensive. Bring all makeup (the variety here is limited across all pharmacy-type brands...which are also x3 the price of anywhere else. Top brands are also hard to find and very expensive). If you use applicator tampons (and won't switch to the other ones), bring them. A specific cream or face-wash, bring it. The only available shampoos are the very basic pantene, sedal-type brands. The same goes for styling products. Nicer bath products - soaps, shower gels, bubble bath, etc (Body shop type things) are of a much lower quality here and smell pretty awful generally. I've also found it really hard over the past year to find a decent bar of soap. I'd always bring back with me some nice bars of French olive oil soap or sandlewood soap when I visited home, which you just can't get here, but now even a regular Dove soap is hard to come by. Theres just lots of Lux-type brands.
Bring clothes. Don't bank on buying things here. Its expensive. The availability of sizes is limited. Most high-street type brands (and even a lot of higher end Argentine brands) are very fond of low-quality, man-made fibers that make (at least my english body) itch and sweat!