It's so great to see you out and about with your X100, Andy! I have to set aside more time to look at your pictures...but I did just do a quick check on Flickr and think that your busker sings in this color version!
If you do not have Photoshop or Elements then yes i would recommend it. The Pro contrast efect is superb as are some of the other efex. You can stack efex on top of each other and play around with them to your hearts content. It really is a great prog. It does for colour what Silver efex does for mono. Check out the vids on youtube and the NIK site before you make up your mind if it's for you.