Unix directory structure: managing file name collision
Usually people choose the name they want and if something collides then the problem gets resolved by the distribution. That's what happened with ack (ack in Debian, Kanji converter) and ack (ack-grep in Debian, text search utility).
Collisions don't seem to be that common though. A quick web search should tell you if the name is used somewhere. If it's not searcheable, it's probably not included in many distributions and that means you're not likely to actually conflict.
Usually when compiling programs, you can usually specify a prefix path like this: ./configure --prefix=/usr/local/prog1 or ./configure --prefix=/opt/prog1 (whether you use /usr/local or /opt doesn't really matter). Then when running make install it'll put the files in the specified prefix path. You can then either 1) add /opt/prog1/bin/ to your PATH or you can make a symlink to the executable file in /usr/local/bin which should already be in your PATH.
Best thing is to use your distributions package manager though.