power conditioner/power cable

Im fairly new to the hifi world but im confused about something.My local hifi dealer advised me not to use a power conditioner/surge protector unit(monster,panamax,etc)to plug my gear into,instead to just use a power strip. is this correct??One other question i have-if one does use on of the previous mentioned devices is it beneficial to upgrade the stock power cables??Any help would be appreciated,thank you.