<human>: Can you give me the gist of the text in a nutshell?

Pretty new runner here. Started running in January 2012. Did first 5k in Feb just to see if I could.  Ran the whole thing, finished in 35 min or so. Was 190-195lbs when I did that. 

Now I am at 160lbs and training for a half marathon (august) and a full marathon (november). I was evaluated at a running store so that I could make sure that I was wearing the right kind of shoes.  They measured my foot, was a US 8, but was told I should get atleast half size to a full size bigger. She brought out one pair size 9 and after I tried them on, she told me to go to a size 9.5.  

Being a vain girl who used to buys shoes for fashion and not performance, comfort, etc... I did NOT want to do this. I ended up listening to her.  SHoes felt great the first few weeks. I am about 6 weeks into training and getting into double digit miles and now feel like I am getting ready to lose a toe nail.  The 2nd toe on my left foot constantly is sore and the nail is wearing away due to all of the room that it has to move around.  No pain on any other toes, or on the other foot at all.  During my 5 mile run this morning, I wore my reg size shoes that i was wearing pre-evaluation and it seemed to feel better on my toe because it couldn't move around. 

I know people lose toenails while training especially the more long runs you do, but my question is... To avoid it as long as possible, should I buy shoes too big so my toes have room to wiggle? or should i wear shoes that fit and make my foot feel stable?
<bot>: need opinions on which is better? shoe too big for wiggle room? or shoes that fit and are more secure on feet?