Olivia is one of the most popular, along with Harmony and Red Tag Sale. But they all have their fans! I like Olivia because of all the extras that come with it. I got Red Tag because I could use it for more masculine projects--the Olivia is pretty girly.
To adhere the letters, I use the Sakura Quickie Glue Pen. I bought mine at Michaels, but you can get them at Archivers or online. It is like a regular ball point pen, but glue comes out instead of ink.