I would suggest reading Code Complete . He understands this issue in quite some detail (devoting him almost an entire chapter) and gives what I consider to be a convincing argument for No. 1.
He actually says not to use the second explicitly, as he did not pass the black box test:
if (blah)
{
}
When a black box turns into:
XXXXXXXXX
X
XXX
X
, , ( ).
( ), :
if (blah)
{
}
:
XXXXXXXXXX
X
XXXXXXX
X
: , ... , :
if (blah)
{
}
. , , . , . . , ...