I missed out on this thread whilst I was 'away', but I like lists (who doesn't!) so will bump it...
Cars I've owned:
inline 3 (turbo petrol) - Smart For Four (0.9)
inline 4 (n/a petrol) - Alfa 156TS (2.0)
inline 4 (turbo petrol) - Mk VI Golf (1.4), Saab 9-5 Vector (2.2)
inline 6 (n/a petrol) - BMW e36 323i (2.5), BMW e90 330i (3.0)
flat 6 (n/a petrol) - Boxster S (2.7), Carrera S (3.8)
v6 (turbo diesel) - RR TDV6 (3.0)
v8 (turbo diesel) - RR SDV8 (4.4)
Other, different configurations
Other's which I've also 'driven' but not owned (oddly never drove my old man's Maser GT which was an omission!) and not duplicating any of the above layouts:
1 cylinder - couple of dumper trucks and go karts
inline 4 (turbo diesel) - Mitsubishi Shogun (1.8?)
v6 (n/a petrol) - Mercedes CLK 320
inline 6 (turbo diesel) - Komatsu PC 210 (6.7 - I think this actually is a Cummins?)
v8 (n/a petrol) - Audi S5 (4.2)
v12 (n/a petrol) - Aston Martin DB9 (6.0), Ferrari FF (6.3)
Never owned anything with a v8, v10 or v12 petrol which needs remedying and never driven a v10 of any description.