I normally do, but I've been having tonsil problems lately and haven't been able to do much...and I'm not supposed to take anything because I'll be getting them carved out soon. Are you asking what works well? If so, then first what are your goals (get lean, bulk up etc.)? Whichever goal you have, first make sure you're getting enough quality protein and also quality calories...note the word quality. This is because supplements are just that...supplementary to your diet. If your diet isn't good, then all the supplements in the world won't help. Also, make sure you're training properly...ie for your specific goal, but not overtraining.
Now if you're diet is solid, then make your building block supplements a multi-vitamin (I like centrum performance or generic equivalent), and essential amino acids (bcaa's) which will help build, or spare muscle when leaning out. The next step is to add a meal replacement (met-rx) and/or protein shake. These are versatile in achieving either goal because they help you get the 5-6 quality meals in every day. If you're wanting to gain, then use regular meal replacements and protein shakes, if you want to lose fat use light and low carb versions. Also, you might want to use conjugated linoleic acid (CLA) and Flax Seed Oil for essential fatty acids (omega 3's and 6's). These are good fats and CLA has been shown to stimulate fat burning if that's your goal (4-6g per day).
The next step would be creatine, which is really just another amino acid. It is useful in recovery, for both gaining and losing. As you break ATP (adenosine triphosphate) into ADP (adenosine diphosphate), then the creatine monohydrate binds with the free P (phosphate) making creatine phosphate (CP). Then during recovery the CP will donate the P to the ADP helping you recover ATP more quickly allowing you to lift more intensely for longer periods of time. Basically, you'll get more out of your lifts. During the loading phase (5-7 days) you will gain about 5+ lbs. which is water weight. It causes your muscles to hold water in the cells, which is why it is essential to drink tons of water (shoot for about 1 gallon per day while on creatine). Also, it will help your kidneys during high protein diets and supplementation.
The next step would be any of the more advanced supplements. Depending on your goals that would be testosterone boosters to fat burners. If you're gaining (or want to spare muscle during diets) you can take a testosterone support supplement, but I would recommend staying away from prohormones (andros) and use anti-estrogen supplements. For burning fat, you can use an ECA (ephedra-caffeine-aspirin) supplement like Xenadrine, but check with a doc first in case of high blood pressure. If you don't want to be on edge...try the ephedra-free version (Xenadrine EFX), or something similar. It has other ingredients. You can also use coleus forskolii, beta-3 and guggul sterones (thyroid support...t-2 and t-3 are depressed in diets), 7-keto-dhea (NOT regular DHEA) and similar products that will act in synergy and enhance each other. That's a bit of an overview, but I hope it helps.
No, I'm not a doc, or guru, but I was a biology and sportscience double major before switching majors and I also do lots of research prior to using anything...and I strongly suggest you do the same. Make sure you have no heart or blood pressure problems if you use a stimulant like ephedra...otherwise you could get into trouble. If you have more specific goals, I'd be happy to offer any advice I can. Let me know. Just send me an IM, or email via this website. Good luck and God Bless!
JR