Peak Testosterone has already given some coverage to many of the nasty, toxic chemicals in sunscreens in my link on The Dangers of Sunscreens. Again, we cannot help but be amazed at the irony of supposedly cancer-protecting products actually likely causing cancer and other health problems. As always, you have to protect yourself: you cannot trust most companies to have your long term health in mind.
The good news is that there are now a significant number of sunscreen alternatives available now that should have a much better safety profile. Some companies (with an apparent corporate conscience) have jumped in and prepared excellent sunscreens without most of the known, toxic offenders. These sunscreens, for example, leave out the avobenzone and oxybenzone, whose likely toxicity I covered in the above-mentioned link on The Dangers of Sunscreens. These two ingredients are in most sunscreens and, until recently, it has been almost impossible to avoid them.
Before we look at a couple of the sunscreens that have made a real effort to be a more "natural" and safe alternative, there are a couple of other potentially toxic ingredients that we should mention:
1. 4-MBC (4-Methylbenzylidene camphor ). This endocrine disruptor is a xenoestrogen  and possible thyroid disruptor.  It also has some UVA blocking capabilites so some manufacturers add it to the ingredients.
2. Retinyl Palmitate. This is a controversial compound. The Environmental Working Group submitted a paper to the FDA summarizing many studies that show that this compound releases reactive species (free radicals) when exposed to sunlight. Furthermore, animals developed significantly more tumors at fairly reasonable doses of both sunlight and retinyl palmitate.  Other researchers have argued that the data is inconclusive, since retinyl palmitate is a natural vitamin A derivative and the product has been used for years in cosmetics without any major issues. 
Most of the popular sunscreens (in the U.S.) have at least 3 of these likely toxic ingredients (avebenzone, oxybenzone, 4-MBC or retinyl palmitate).
So are there any decent sunscreen alternatives? Are there any sunscreens that may actually protect you from skin cancer instead of helping to induce it?
Below are some brands that I have tried with good success:
1. Aubrey Natural Sun. This brand avoids the chemical ingredients altogether and relies on good ol' zinc oxide instead. Of course, the problem with zinc oxide, especially for light skinned folk, is that zinc oxide can create a ghostly effect and actually highlight wrinkles. However, Aubrey's SPF 15 Active Lifestyles uses a variety of oils and extracts in the product that almost completely mask these effects. NOTE: Other Aubrey sunscreens with zinc oxide do not have this same property. Again, my advice is to stick to Active Lifestyles if you're a low pigment sort of guy.
2. Alba Botanica. Another very similar product is Alba Botanica Mineral Sunscreen. This sunscreen relies on zinc oxide and titanium dioxide, both sunblockers and not synthetic chemicals sunscreens, for UVA protection. I mention this product, because it is easily the least expensive alternative that I have found. However, if you are fair-skinned, it will likely give you somewhat of an early 90's Goth look.
2) Robert Finn. Skin & Allergy News. Sept 2010 v41 i9 p6(1), "Few data to support retinyl palmitate concerns"
3) Journal of the American Academy of Dermatology 63 (5): 903â€“6, "Safety of retinyl palmitate in sunscreens: a critical analysis"
4) Endocrine Abstracts, 2006, 11, OC60, "4-methylbenzylidene-camphor (4MBC) causes pituitary effects comparable to hypothyroidism"
4) Toxicology Letters, Apr 2003, 142(1-2):89-101, "Activation of estrogen receptor ? and ER? by 4-methylbenzylidene-camphor in human and rat cells: comparison with phyto- and xenoestrogens"