Good choice for a little dog?

We recently lost our dog marley, (a white german shephard golden retriver mix) some evil person ran her over on pourpose on our own property. but we realy miss having a dog. now we live in a appartment and we want to get a small lap dog. were not sure on which little dog would be good for us. its a huge change for us because we have always had large dogs (german shephards). our neighbor has this little shih tzu. we love it because its so spastic. my dad is a long haul truck driver and wants to take the dog with him on the road. so we need to know what dog is good for us. we need a breed of dog that is okay to travel alot...and be a lapdog. it needs to be like a toy/small breed due to the appartment and truck. so we did some research on a href="http://www.terrificpets.com/" rel="nofollow"http://www.terrificpets.com//a thank you all for your help.