My suggestion would be to go north. There's a lot to see there. If you enjoyed MP you might consider going to Chachapoyas and visiting Kuelap, a pre-Hispanic mountaintop fortress that is equally spectacular and a lot less heavily trodden. Also around Chachapoyas the Gocta Falls are worth visiting.

Cajamarca is also interesting historically, for many of the same reasons that Cuzco is. And if you're really into adventure, rent a 4X4 in Cajamarca and drive to Chachapoyas. It's a spectacular and sometimes hair-raising journey.

Also of interest in the north is Trujillo. Further north are the beaches of Los Órganos, Máncora and Punta Sal. This area has a very different flavor compared to the beaches to the south of Lima.

Enjoy...