Apart from Via del Corso and via condotti, a very nice shopping street is Cola di Rienzo near the Vatican. Here you can find almost every shop found in via del corso , however shops are much less crowded.
It's another way to go shopping. PortaPortese it's just a second hand market where you can find whatever you want. There are hidden gems in the middle of the 'cassino' (chaos). It's wonderful... Each sunny Sunnday... on the other side of Tiver's river.