LVM or not? Install Breezy

[Walt Bankes]

Installing Breezy requires one to pick if they want LVM or not.
I found lots of info about LVM. So now I know what the acronym stands 
for but all the info I found was either too esoteric or too terse for me 
to make the decision whether to install LVM or not. Will someone please 
tell me what advantages LVM gives me when I install it on a Ubuntu only 
system (two disk drives)  and what possible disadvantage there may be.
Thanks, Walt Bankes