I've used LED's from Pinball Centre (Germany), Ministry of Pinball (Netherlands), Pinball Heaven (UK), Pinball LED (UK) & Comet (US). As much as i'd like to support the home grown company, I'd say Comet has the best selection by some margin.
If you want to enhance the colour of the inserts, pick a bulb colour which suits - that's going to require you sitting down, mapping out the inserts (little spreadsheets help) and recording what you need before ordering. Or buying a pre-made bundle for that game.
Or you could just buy a load of generic warm white LEDs and put them in everything - not much difference or benefit from using standard bulbs, but possibly cheaper than individual colours and much simpler.
The lighting effect with LEDs can be very harsh on then eyes given the brightness and blinky ON/OFF nature. You could use a an LED OCD board to smooth this effect out, but as the title suggest - it's a bit OCD!
e.g.
You can customised areas of the playfield with your choice of GI colour though. For example, i've used blues and purples in the back-left corner GI of my Spiderman (Venom's bit) and Greens on the left (Green Goblin's bit). Including coloured flashers (Comet's flashers are really good:
http://www.cometpinball.com/product-p/8smdg18tower.htm)
Note - I have no real experience with DE games.
I've also noticed that some LEDs are not quite big/fat enough for the sockets and can work loose if the LED isn't pointing vertically (like they are under the playfield). e.g. the spot lights on the Spiderman Playfield point horizontally at the villains, and the slingshots vibration nearby seems to work the bulbs out over time. If i was operating this game, i'd either use a glue gun to stick them in, use regular bulbs in those sockets, or leave the bulb out entirely.
