<p>Thank you all for your advice, i find all the opinions very useful!<br>
<br />I've been asked about how i use my gear... well i mostly do urban and landscape photography, when i travel i come back with 40% of the photos with the 10mm focal length and around 70% in the 10-20mm range. Sometimes i think that i'm abusing the ultra-wide style and i should take photos with less distortion, that's why i've decided to invest in a good quality mid-range zoom to challenge my sigma and push myself to diversify my photos. I barely feel the need to have something longer than 70mm or so, 5% of the time as much and that isn't enougth for me to justify carrying a specific lens<br>
About the aperture topic, for me f2.8 is not only a question of low light situations but about the quality, the colors and the light that these lenses obtain, i mean bokeh and out of focus pictures that brings me a lot of creative options. <br>
Another aspect that i take into account specially in the last years is carrying the minimum weight with me, having a full photo-filled backpack with me all the time is a pain in the ass sometimes and i'd like to stick to the minimum... that's why i'm not interested in full frame (at least in the short term)<br>
here is my flickr if you want to see what i usually do: https://www.flickr.com/photos/29324944@N00/</p>