Sorry to hear about you losing Susie, Boffin. We lost our Sheltie, Jackson on December 16, 2011, and even though we have another great Sheltie now, I will never forget Jackson. No one who ever knew him ever will.
In my humble opinion, I believe that you have a talent for choosing what I consider to be the best breed of dogs. Our first Sheltie, Jackson, passed away too soon due to a horrible disease. He lived to be 10 years, 6 months, and 1 day. <----That is a photo of Jackson in my avatar. If you click on "Best Friend" in my avatar, you can see a full size photo of the photo shown in my avatar.
We got Phoenix on March 3, 2012, and although he has grown up to be very beautiful and athletic, he looks and even acts considerably different from Jackson. The main differences are the color, the floppy ears versus Jackson's straight ears, and he does not exhibit the same exuberance for diving into our swimming pool that Jackson did.
This is Phoenix as of today:
I know you will enjoy Luke, and hopefully both he and Phoenix will last a bit longer than Jackson did.