I used to get mixed up with Josh Howard and Marquis Daniels when they were emerging in Dallas. These two were rountinely confused by the other broadcasting crews. Graham who? Not anymore but in a similar fashion as Thorton and Young I don't know which is which, to me they were one entity, one and the same.
At one point or another, I've mixed up... Al Horford and Al Thornton Brandon Roy and Randy Foye (pre-draft) Jonathan Bender and Al Harrington
Different sports, but I always get "Drew Gooden" and "Dwight Gooden" mixed up. I think because Drew Gooden used to play for Orlando, and my brain associates "Dwight" with "Orlando".
Last year I kept getting Casspi and Ilyasova mixed up mainly because watching the Bucks or Kings play isn't exactly an edge-of-you-seat experience.
Maurice Evans and Matt Barnes I used to always call David West, Doug West, even though Doug West hasn't been in the league for about 15 years.