Lapras @ ???
Shell Armor / Hydration / Water Absorb
252 Special Attack / 200 HP / 56 Speed
- Surf / Hydro Pump
- Ice Beam / Freeze Dry
- Psychic / Dragon Pulse
This is a very basic EV spread and moveset. Surf if you don't have another decent 'mon to use it, mainly because Hydro Pump's accuracy cannot be depended upon in game and you don't need the extra base power. Psychic and Dragon Pulse for general coverage. Psychic is preferred over Dragon Pulse, what with all the Fairy Pokemon and Ice Beam to cover Dragons. Freeze Dry is another option that you might want to consider, but isn't recommended.
This spread works decently in-game. There is a little investment in speed, but it could be put into other defenses if you want. Lapras is sluggish so it might end up being a waste. That said, in-game it's all right to invest in speed. Totally your call, to be honest.
For competitive use,
Lapras (F) @ Choice Specs
252 Special Attack / 140 Speed / 116 HP
- Hydro Pump
- Ice Beam
- Thunderbolt / Freeze Dry
- Hidden Power [Ground]
Also a standard set, from Smogon, but with minor tweaks. There's not much to this set, mainly because Lapras doesn't have too many choices it is good in. A Perish Song set can be used, just for the sake of it if you want, but again, not recommended.