Nearly any distro will work for your needs except for gaming, you need to be aware that windows games will not work in other operating systems. There are some software layer libraries like wine, crossover games, etc.. which will allow some games to be played, but as it is noon-native there will be bugs and some programs just won't work.
As a starter you shoud checkout linux mint or ubuntu as they are user friendly and have large software repos, you can also test them from a CD to test the interface. When running any OS from a disk the experience will be slow because all data must be cached into ram, so they speed will differ on disk compared to being on the HDD.
As for relaibility, stability and security those are the best reason to try linux, the large community or developers and active contributors help to ensure that most bugs are discovered and resolved quickly.