4:46, which is the highway on which my best friend, from ages prebirth to 32, lived. She was almost 10 months older than me. My mom went to see her and her twin brother when they came home from the hospital, and must have gotten pregnant with me about the same time period. I was not a planned child.
We were best friends until she died in a car wreck at age 32. 13 years later, I still miss her. I like to think it's a poke from her saying, hey, remember when...
And I think that's why I notice the time. I glance at the clock at a lot of other times, but those times don't register as "Wow, every time I look at the clock, it's 4:46" since those other times don't have something special associated with them. I'm sure I look at the clock a lot when it's 8:16 for example, but I don't get that brain nudge since that number combination isn't special to me.
Oh, and I also seem to notice 12:34 a lot, probably just because of the sequence.
I think it's more of a poke when my last car shared her birthday. You could find out when Saturns came off the assembly line, and my was "born" on what would have been her 40th birthday. Ought of all the Vue's on the lot, I picked that one. I named the car after her.