Think Allan's hit the nail on the head-
If I could only afford one name in one ccTLD, I'd personally go about picking it this way:
First I'd see if I could get co.ext (easily the best LL choice)
Then proper LL words are a good bet (tv, my, me, be, of, on, at, go, it, to, in)
Perhaps non-english LL words too (e.g. de, ce, ca, le, ma)
LL combos with the same letter (aa, cc, ss)
The usual rules about premium vs non-premium letters would affect my choice
I'd also consider a copy of the extension i.e. if it was .vg I'd get: vg.vg
Next, I'd consider a domain hack e.g. ha.ms
Finally, I'd consider country codes e.g. uk.ext us.ext de.ext se.ext (but only the larger online countries)
I don't think I'd get just any old LL.ext, as there's too much choice- it is likely the domain may never sell for much, and the annualy charges on most of the ccTLDs that offer LL combos are too high for pure speculation (IMHO)