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[Anbesol]

If youre working with a tight budget, ditch the kit lens for sure. Its another $100 that can be used towards much more useful things, flash accessories, better lens, tripod, case, spare battery, etc etc. On the other hand, its a dirt cheap lens that you can use a bit more recklessly, or as backup, etc. My main reccomendation is that, if you DO get the kit lens, be sure its not the only lens you get. The Tamron 17-50 f/2.8 is an excellent alternative to the kit lens and a very killer price too @ only ~$400.

There are plenty of other options though, try not to be swayed by those superzooms that promise versatility, they make a huge sacrifice to optical quality to put that huge range in.

The macro lens makes for a poor sports lens because sports lens require very fast AF, and Macro lens have huge focus range which inhibits AF speed. Most macros are ~ 50-110mm too, which is way wide for most sports.

A lens ability to macro is measured in a ratio, the relative size of the actual object to the size on the sensor. 1:1 Is a true macro ratio, but there are several lens that offer 1:3 or 1:4 which is also very close and close to macro. That kind of lens would be much more multipurpose and much better for action photos. Tamrons 70-200 f/2.8 has a 1:3 magnification, and has super fast AF, would be much faster AF then the 100mm you mentioned, but not quite as macro.

Also - the mag is 1:3 at 200mm, as opposed to the 1:1 at 100mm. You'll need to zoom all the way in to use the tamron at 1:3, which is true of any magnification ratio on a zoom lens.

What are you wanting to do with your saltwater tank? Maybe 1:3 would be adequate, as 1:1 you see lots of things the human eye cant.

I included a sample of a shot taken at ~1:6 as reference, and a 100% crop.