get the dme kits they have better shelf life. and dont need cool storage.
Many of the major online stores include LME in their kits. NB often uses a mix of LME & DME. MoreBeer offers DME as option - but there is a price difference.
Generally, if one isn't going to brew promptly with a kit, it's a good idea to store
- LME in the fridge
- hops in the freezer
- yeast in the fridge
Remember to store the LME cool on arrival and brew promptly.
There was a recent topic over in
/r/homebrewing (link) where someone stored an LME IPA kit at room temperature for "at least" six months before brewing. The topic was interesting to watch, as that OP didn't initially mention the delayed brew day or the storage conditions.
My limited experience with LME suggests that
1) oxygen barrier bags (with no "head space") and
2) high turn over (at the on line store)
result in a product that arrives fresh. I need to
1) store it cool (fridge) and
2) brew with it promptly for best results.
i didnt like dme cause the first time i tried it it clumped and was a sticky mess. dme is much better than lme tho and when i employed the no steam warm slurry trick it turned out to be a no brainer over lme for me.
In warm & humid environments, DME can easily become a sticky mess.
@D.B.Moody 's approach (in the 'I brewed a favorite recipe today') is a pleasingly simple way to avoid the problem.
OTOH, both MoreBeer and Williams offer interesting LME products - well beyond the common DME styles: pilsen / light / pale ale / wheat / amber / dark. I've had good results with a couple of the Williams LMEs (shipping was in early spring).