this might take some time to compile... I'd better start a list

(first problem is, I've not actually bought many BIKES per-se - BITD, gruppo's didn't change every year as a fashion thing, so you bought you're Campag Record groupset, and just swapped whatever you managed to damage in crashes as and when. So, It's probably best to list frames... Second Problem - I often had frames re-finished in a different colour)

first bike - dunno name, catalog special when I was 4-5 y.o. - Blue
second bike - Raleigh 14" wheel kids bike - Blue
first "real" roadbike - Bronze (hammerite, handpainted, rough as arseholes but I loved it because it was my bike)
Raleigh Lenton Sports - Green
Carlton Pro 531 - Silver
Woodrup Custom - Red
Bob Jackson 531 Custom - Red
Bob Jackson 753 Custom - Red
Raleigh TT Frame - White
Alan Cyclocross Frame - Silver
Holdsworth Fixed Gear Frame - Orange
Raleigh 531 - White
Raleigh 531 - Red (old TI Raleigh Colours!)
Raleigh 531 commuter hack - White
Bianchi Track Frame - Chrome
Raleigh Thunder Road (hybrid commuter) - Black/Green
Pace RC100 MTB - Silver
Raleigh Odyssey MTB - Silver
Dawes Galaxy - British Racing Green (re-stoved in Black)
Dawes 531 winter Hack - Red (re-stoved in Blue following season)
Raleigh Dynatech 753 - White
Pinarello Treviso - Blue
Bianchi (forget the model, Columbus Cromor) - Celeste (naturally!)
Colnago Master (art Deco) - Blue
Raleigh Dynatech 701 - Black (with very loud stickers!)
Planet-X superlight Alu - Blue
On-One Inbred 456 - Red
Dolan Tuono SL - Black/White
Cannondale CaadX 105 - Black

(there's probably another half a dozen or more that I've had, kept for a week/month and punted on (used to moonlight at a bike shop in my teens, and suplemented my wages/built up my bike fund by buying, restoring and selling bikes!), but all of the above have been regular rides...)

so I guess it's red and blue tying for first place with 6 votes each, then a tie for third with Black and white on 5 votes each (though, in fairiness, I think I'd give the vote to Black, as the Tuono IS really more black than White, it's just that from the saddle, you see more white than black...)

If I figured in all the other bikes I've had on a shorter term, then it'd definitely get complicated, but I'm thinking that RED would come out on top - mainly because the local stove-enamelling company used to do such a fantastic "Flamboyant Ferrari Rosso" finish that nearly all the ones that I re-furbed and had re-stoved ended up in that colourway...

I haven't owned many cycles over my lifetime, but here goes...it is a short one, and the only repeat is black!

1. Red tricycle from when I was maybe 3 years old. I got it for Christmas and had to ride it even though there was two feet of snow outside. My Dad obliged tho!
2. Orange Chopper-style bike with banana seat bike typical for the early 1970s, with three speed hub. God, I loved this bike and rode the hell out of it, on-road and lots of off road.
3. Blue 10-speed typical of mid 1980s. Might of been a Schwinn but I don't remember. Rode this all over until I destroyed it in a crash. Then quit cycling for several years.
4. Black dept-store mountain bike (circa 1993). Rode this for a few years then sold it.
5. Brown-ish Fuji I got for free (and still use as commuter bike)
6. Black Moto MTB
7. Green/White Cannondale Synapse

'60s - 2 tone blue 'Triumph'
'70s - Halfords bike ?. Yellow, then respray to red.
90s - Maroon /silver 'Townsend'
" - Dk Green 'Rigeback'
2000+ Slate grey 'Cannondale' CAAD Hybrid
2013 Silver 'Dawes' folder/shopper. Easy for having had Hip-replacement.
Now.. Dk Grey/red 'Giant' Escape. Can get 'leg-over' now and planning to be ready for spring. Road/path countrylanes..

No consistency, although it leans darker, kind of.
1: silver/blue BMX
2: cola colored 10-speed (supposed to look like Dr. Pepper...yes, my dad won it in a sponsored by Dr. Pepper and gave it to me replete with Dr. Pepper logos)
3: purple Trek MTB
4: red Specialized MTB
5: black Marin hybrid/advednture

So nope, no consistency.

Pretty much black. My first $400 hard tail MTB was black, then a white hand-me-down FS MTB, followed by my current black with green accents MTB, and my black w/ red accents CX.