Since you are concerned with both biological and chemical contaminants, you can narrow the field down to primarily filtering devices. Products such as the Steri-pen, MIOX, AquaStar and most chemical agents are designed only for biological contaminants. There is at least 1 chemical chelating agent designed to reduce chemical contaminates, but I would not recommend that product for personal use.
Many have already posted the better known, tested and established products, which will likely serve your needs. When selecting a particular model, also consider the anticipated needs of potable water. It might be better to select a model that has a higher output then you anticipate, as your needs for both you and any traveling companions might be higher then expected.
If possible, go to a local REI or similar store and talk with the staff, play with the display models and look at both the accessories and replacement items (filters, chemical additives, etc.) before buying.
As to what I carry:
I have several systems that I have and use. My main use has been during my trips to Ecuador. My personal and primary system is a Katadyn Exstream Purifier, which I carry everywhere, including the plane. I also carry in my check-in luggage a MIOX, MRS Sweetwater Purifier System and a Steri-Pen. Keep in mind; I am the “go-to-person” on our medical missions, so I have redundant systems for many applications. I have used the various systems to generate both drinking water for the group and water for medical applications (wound/ear/eye- cleansing/irrigation, etc.).
Pete