I like the following a bit better as you don't have to find out how many rows you're going to affect before affecting them. YMMV.

declare @rowcount int

set @rowcount = 1

declare @batchsize int

set @batchsize = 5000

while(@rowcount > 0)

begin

delete top @batchsize from table where foo=1

set @rowcount = @@rowcount

end