I value the lively ride you get from flexible sidewalls and prefer to watch weight of all components and gear pretty closely. I don't obsess if I have to fix a flat once in a while. Given that, I find Continental Gatorskins to be a pretty good choice. I run lightweight tubes either a size smaller than recommended or at the small end of the recommended range. That makes tires easier to mount, yields a livelier ride, and saves a good bit of weight since we are talking about two tubes in the tires and two spares.
BTW: I tried Marathon Pluses briefly and hated the dead feeling ride and the extra weight. I disliked them enough that I took them off after just a few hundred miles. For folks who are really averse to getting a flat once in a while I guess they are the ticket, but they should realize that the Plus weighs more than twice what something like the Gatorskin does, have a very stiff sidewall, and are generally a very low performance tire. They are apparently very long wearing, but I consider that a long sentence to a dead feeling ride. I'd consider them for a short commute on very glass strew roads, otherwise no.
If in goat head thorn country I have found that the following steps minimize tire problems:
- knowing what the goat head plants look like
- avoiding green stuff growing in the cracks of the shoulder
- staying on the pavement
- checking for and removing any thorns before resuming any time I do go off of the pavement at all