I was fond of Ariel Rounded Bold for my songbook, but the print-on-demand people I use to print it did not have that unless I embedded it (which I do not know how to do), so I use Ariel Bold in 12. Bold helps to see it. Since most of what is in my songbook are long ballads, it is important that lines fit on one line - the book is 350 pages already. It is a compromise between big enough to see and keeping the ballads to no more than three pages.