hey, would it be better to upgrade my epiphone LP-100 with some very good pickups and whatever else or get an LTD EC-400 AT
If you need a second guitar then buy another, but if you can manage with just one one then an upgrade would be cheaper and make more sense
(='.'=) This is Bunny. Put him in your signature and help
(")_(") him on his way to world domination.

"Arguing online is like racing in the Special Olympics- Even if
you win you're still retarded."

"You cant spell crap without rap"
Would it be better? I am sure that a new LTD EC guitar would be better than an LP100 with new pups.

Guitar fetish has good cheap pups if your interested.
Personally, the LP-100 is just a beginner axe.
Overall, even if you did upgrade the pickups, it's still a beginner axe. Aim for something a little higher.
My newbie stuff:

Ashton Acoustic (forgot model :P)
Squier Stratocaster
Fender Frontman 15R


Saving up for...

Vox Valvetronix ADVT50
Boss D-2 Pedal
Les Paul Studio (Wine Red)