The thing is, l820 is just boring. What can you do with it except calling and texting? I don't think about myself as a geek but I like to do some stuff with a phone. Even with symbian I could do some modding in firmware and I know you did that too (I didn't like your cfw but it's not the case). I cannot tell you which one to choose, these are too different phones for two different markets. I'd pick L820 if I wanted to focus on my studies and use a phone for calling, texting and web browsing. L820 is also good if you don't have a car as the touchscreen is sensitive enough for you to operate in regular gloves while it's quite cold in Poland recently.
It's a tough decision and only you can make it. I'd say go for l820 if you want to leave any forum activity or stay with us with N9 and I'm sure the community will not disappoint you.