I didnt decid what macro lens i will get yet, but you have a good point, since my dad will use the lens mostly, and he has a crop-sensor camera, i maybe look into a different focus length.
About the light, you are 100% right. I have no experience with lightning. One person told me to switch the flash out to the newer Phottix Mitro+, since it system works way better than nikon's in a off-camera situation with lot of sunlight. He recommended me that kit:
Phottix Scott Kelby Mitros+ TTL Flash and Odin TCU TTL PH80378, which costs less than the sb-910 itself. What would you recommend?
You need to decide what kind of flash photography you want to do. For professional quality results, you basically cannot fire the flash directly straight-on to the subject, except as fill flash in bright sunlight.
If you want to do studio portrait photography, then you should look for three studio flashes with big stands and diffusers. If you want to do wedding photography, you need more portable equipment. If you do event photography, such as weddings and business functions of people indoors, then you want an on-camera flash that's very powerful, (maybe an external power source) as well as a diffuser of some type.
So, unfortunately, it really depends and it takes work with the equipment to decide what you want. Another really popular piece of gear are "radio poppers," which remotely trigger your flashes using radio transmitter/receivers. One excellent book I recommend is Syl Arena's Speedlighter's Handbook. He is Canon-based, but everything he does can be done with Nikon. Another resource, which is more budget minded, is
www.strobist.com. Although he recommends very low-cost equipment, the techniques can be used with any kind of equipment. The Strobist-recommended equipment isn't very durable, which you'll learn the first time yuk use an umbrella and flash on a lightstand outdoors. As soon as a gust of wind blows, your equipment will fall over and break.