Odd that nobody has thought to poll this yet. Here we go. I allowed multiple choices in this poll, in case someone really can't make one preference.
I choose Fredrik Johansson, Mikael is great on Skydancer, but it's obvious he's not in the same class as Niklas. Fredrik on the other hand compared and complemented Niklas favourably, and his guitar style had a larger impact on the DT sound. For some reason I've never got a good feel for Martin's style, maybe it's a bit generic overall, but I feel like they traded in a great bass player for "just" a good guitarist. I recall reading that Martin and Niklas alter the leads, with Niklas handling most. I'm not sure to what extent Fredrik played leads, but I think Niklas played all of them on Skydancer.
I choose Fredrik Johansson, Mikael is great on Skydancer, but it's obvious he's not in the same class as Niklas. Fredrik on the other hand compared and complemented Niklas favourably, and his guitar style had a larger impact on the DT sound. For some reason I've never got a good feel for Martin's style, maybe it's a bit generic overall, but I feel like they traded in a great bass player for "just" a good guitarist. I recall reading that Martin and Niklas alter the leads, with Niklas handling most. I'm not sure to what extent Fredrik played leads, but I think Niklas played all of them on Skydancer.