I have an i7 2600k (8 core) which goes through LTC like butter but coughs at BTC, so I mine LTC on it and BTC on the GPU. It all depends on what hardware you have available and usually laptops are not worth using to mine because although they may give you a return, the mining will surely destroy the life expectancy of the laptop (not enough cooling, continual use, will destroy everything, and the battery... fry the hdd oh the humanity...)
however if you use cgminer and put the aggression down it wont do it much harm
Thanks muubam. TBH the fan on the laptop I have goes nuclear even for light browsing so I'm not going to risk it. I'll have to stick to mining BTC on my desktop and maybe switch to LTC if and when the ASICs show up.
On a sidenote I would never buy another sony computer again. They should stick to TV's