to do list vs To-do list

Some examples from the web:

• A to do list is a highly effective tool.
• Kives, "To do list." Look, "Finish coding."
• On their to do list, I'm sure.
• You didn't really have it on a to do list, did you?
• It led, with the Commission's impetus, to a series of reforms, which were listed in Romania's famous 'To Do List', under which the Romanian authorities put greater emphasis on improving political and economic governance.
• We wanted to get pregnant, and four weeks later I was ticking it off my to do list.
• To display the to-do list view, press the To-do List View toolbar button, or choose the View To-do List menu item.
• So while Eli finished his ghost to-do list, I spent the whole day finding out passenger information.
• Looks like Niklaus had a lot on his to-do list last night, and as for Hayley...
• Kontact handles your e-mail, address book, calendar, to-do list and more.
• Your life's to-do list must be a baffling document.
• Here's the first name on your to-do list.
• No, all I saw was an old pack of kools... and an unfinished to-do list.
• You just made my to-do list.
• Hometown security is next on my to-do list.
• I guess you could say success was always on my to-do list.
• I was simply autographing what I consider my most masterful to-do list yet.
• Somebody just went to the top of my to-do list.
• I'm now on her to-do list.
• The to-do list is clear on this count, I think we all agree.

Some examples from the web:

• [Record invitation in my to-do list]
• It's another check on my to-do list.
• But I have barely scratched the surface of my to-do list.
• KitchenSync synchronizes your e-mail, address book, calendar, to-do list and more.
• Enter short description of the to-do into the Title field. This description is the text shown on the & korganizer; To-do list.
• Kontact handles your e-mail, address book, calendar, to-do list and more.
• I imagine your to-do list was pretty long at that point.
• No, all I saw was an old pack of kools... and an unfinished to-do list.
• We cooked up a little to-do list for you guys, too.
• Here's today's to-do list.
• That looks like a to-do list.
• This is our to-do list for our wedding.
• The keys... and your to-do list.
• That is a very long to-do list.
• Defiling her corpse has just made number one on my to-do list.
• No, this is my to-do list for the snowball.
• Finding Elijah didn't make my to-do list today.
• I never thought of Joy as someone who has a to-do list, but it turns out she was a pretty busy lady.
• So this time, there's one less thing on his sick, twisted to-do list.
• Switch the display to the to-do list view.