I would certainly agree with Tim -- there are so many tourists now that it is unbelievable. The first time I was at Jökulsárlón was in July 2005, and there were perhaps 40 people there. It felt like a huge crowd after hours of driving and seeing hardly anyone. I was there last August and there were several hundred people, along with loud speed boats and cars everywhere. Unfortunately, the secret is out about Iceland. This is not to say that these sights are not worth seeing, but the further you head from Reykjavík, and the further from route 1 you go, the more majestic it will be. At least at this time of year...
You have a number of great places on the list, but there are quite a number indeed. Even with 10 days, driving around the entire country is quite a bit of time on the road.
You also might find that a standard 4x4 is not enough to get to some of less accessible places, such as Landmannalaugur...your rental company might not want you going through rivers and so on, and I think you need to go through a few to get there (there are a few routes). This season has been the coldest and wettest in decades, so a lot of the highland routes are just opening and meant more for true offroad jeeps that have been lifted and fitted with extra large tires and snorkels. They should not be attempted by people without experience. That said, there are many many roads and routes that are just fine, even in the highlands. The bottom line is to find out about the routes from experience people beforehand, if there is any question.
The road directorate has a hotline you can call if you need any advice:
Search the web | Road conditions and weather | English | Vegagerðin
They also have a page with the traffic signs and their meanings -- they are not in English. There is also a video on driving in Iceland. I highly recommend you go to this page as well:
safetravel.is | The official source for safe adventure in Iceland
The Met Office has very good forecasts and information in English. The weather here can be dramatically different in different areas, and it changes rapidly, so be aware. I have seen snow in every month of the year other than July. For example, the lowest and highest temperatures today were 2.9C and 26.1C...
Home-page - Icelandic Meteorological Office | Icelandic Meteorological office
In terms of gear -- it is really up to you. It does not get that dark here at this time of year, even in the middle of the night, so if you are shooting film, you will not really need anything about 100, but you can bring 400 of course if you want. You probably will not need your Noctilux! The landscape is very broad, and photographers react to this in different ways. I mostly shoot normal lenses, but some want to capture everything with super wides...Personally, I do almost everything with the equivalent of 35mm to 100mm. Slightly longer lenses can be useful as the views can be very long indeed, and if you want to focus on something in the distance, a slightly longer lens can help. a 75mm or 100mm equivalent will likely be quite useful.
In terms of the hotspots...I dare not reveal all my secrets, lest they all be inundated by tourists googling this
)), but I would say the Eastfjords are my favorite part of the country. You list Reyðarfjörður, but in my opinion most of the other fjords are prettier. In particular, Borgarfjörður Eystri is gorgeous and will have many fewer people. Seyðisfjörður is more picturesque and has better food, such as at Skaftfell...though there might be a lot of tourists, especially if there is a cruise ship in town. Eskifjörður is well worth the trip from Reyðarfjörður, if you are staying there. In Egilsstaðir, it is worth traveling down the river, lagarfljót to visit the forest at Hallormsstaðir, and the interesting cultural center and house at Skriðuklaustur and Vatnajökull information center. The restaurant at Skriðuklaustur is very good, and the setting is very beautiful and peaceful.
If you are on Snæfellsnes, Grundarfjörður is indeed a very nice town, but you should also stop at Buðir on the south side. There is a beautiful all-black church in a stunning setting. It is right next to a fancy hotel that serves a great lunch, dinner or just a coffee. Much nicer to lunch there, than in Arnarstapi, for example.
In the south, don´t miss Dyrhólaey, and take the extra time to drive or climb up the top to see it, particularly if it is a nice day. It gives incredible views over much of the South. It is one of my favorites.
There are so more that it would be difficult to go on, but I hope this will help you out. I will be here at the time, so feel free to contact me if you have any questions or if you want to drop by the studio.
Best,
Stuart