Hey Jason, as with everything, there are lots of different ways to go. I'll give you a few thoughts.

The brightest, widest casting bulbs that we have at Comet are Opmax: http://www.cometpinball.com/product-p/opmax.htm

The only downsides to these are they are the most expensive (but you'll probably only be buying a few per game), and they are tall, meaning they may stick out a bit from shorter reflectors. You can actually see some pics of that in action in our Fish Tales kit: http://www.cometpinball.com/product-p/kit-fishtales.htm

Stern uses 2SMD clear top bulbs in the spotlights of their modern games, which also work great. (These are the same bulbs they use in the GI as well): http://www.cometpinball.com/product-p/2smd-ct-ft.htm

You mentioned Magnums. These are something that I do kind of like as a spotlight, particularly because the light is directed enough that you don't need a reflector at all. You can see an example of that on top of the slingshots in our LOTR kit: http://www.cometpinball.com/product-p/kit-lotr.htm

The Magnums focus the light more than any of our other bulbs, so doesn't spread as widely. This might be great depending on the look you want. Also, I'm finding that these will get hit often by the ball and knocked out of their socket if you don't add a hex standoff to raise them away from the playfield.

We don't have hex standoffs listed on our site yet, but a whole package of them just arrived yesterday...so if you're interested let me know and I can add them for sale before orders start shipping out again on Tuesday.

If you have a reflector where you can just see a little bit of the bulb poking out, and you don't want that, you could go with a bulb that doesn't have a lens. Our 1SMD bulbs have that option, as do the 4SMD bulbs.

Hope that helps a little!