Answering the call of Chemjobber’s Favorite Things About Chemistry, here’s my list:
10. Parafilm (for sealing reagent containers — love how it stretches and conforms).
9. My Chemis-Tree that I set up every year at Christmas time decorated with molecular models and periodic table squares for ornaments. Benzene is the star on the tree. :)
8. My 350 mL beaker coffee mug.
7. A UV/Vis (or any instrument) calibration curve with r^2 > 0.99999.
6. Spotlessly clean glassware.
5. Ependorf pipettes (bulb + glass pipettes != fun!).
4. The thermite reaction (wikipedia) and grain elevator explosion simulation.
3. Tiny glassware.
2. Pilot extra-fine V-Ball Black pens (for labbook documentation).
1. Molecular model sets — the chemist’s Lego’s!