Think about what you want to do, and what you would like to do--

There are a lot of software options,some are expensive, others don't offer a lot of options--are you just looking for lead sheets, or do you want to to do full orchestrations? Do you want to simply enter notation from a typewriter keyboard, or do you want to do want to do entry from a piano keyboard? Do you want it to read and notate MIDI files? Will your files have a lot of pages? Do you want the option to change the appearance of the staff?

One thing to remember is that some programs, like FINALE, have frequent and expensive updates--

Also, I use Mac (which tends to be a standard platform for music and graphics)--I invested a fair amount, over the years, in notation programs and upgrades--now that OSX, the Linux based operating system, has replace the old Mac OS, I am in the position of either using an OS that is obsolete with unsupported software, or buying all new software--So think about what you'll be doing in a couple years--