The right FOSS license choice for a particular FOSS project depends upon a number of factors. Copyleft licenses, such as the AGPL, GPL, and CC SA licenses, are great for requiring downstream users/distributors to provide their improvements under the same license and creating barriers to closed-source use but can also have a negative impact on project adoption. Permissive licenses, such as the MIT, BSD, and Apache, are great for encouraging widespread adoption, but do not impede closed-source use of the software. Weak (or file-level) copyleft licenses, such as the LGPL, MPL, and EPL, offer a middle ground with a less expansive copyleft effect that more users can accept while still requiring distributed modifications to the FOSS project to made available under the same license.
Further, even if you have decided on the GPL license, choosing version 3 is not an open-and-shut case. Due the GPL 2 and GPL 3 incompatibility, a project that intends its software to be directly combined with existing GPL 2 code, such as the Linux kernel, would probably be better of choosing GPL 2 rather than GPL 3. Further, while the GPL 3 patent provisions may help users and distributor of the software, the patent provisions may also impede adoption of the project among relevant patent holders. Accordingly, when choosing a FOSS license, FOSS projects should consider a number of different factors including the need or desire for access to and use of downstream modifications and combined software and the need or desire for widespread use and adoption.