Personally, I think climate change is my top priority as that will ultimately decide whether capitalism can be reformed or not. We cannot have an economic system which actively works to break down the ecological systems which we rely on for agriculture, fisheries, fresh water etc in the long run
. I'm not sure how things will pan out as capitalism is potentially capable of reforming itself, but it really hinges on whether it is in the interests of the ruling class to do so and put those reforms into practice. It won't simply decide the socialism-capitalism debate in one country but the world over. Pretty much all other issues will end up being decided by how they fit into this bigger picture.
In the short-run I don't know as the left is in retreat on every front and has been for a number of decades. In the UK, I'm hoping the Greens will do well in the election this year, but they're still 'progressive' rather than openly socialist even if they have a socialist wing. I am extremely encouraged by the sudden growth in their membership, in-spite of the fact the media really isn't talking about them.
The Far left is an absolute mess- Wikipedia illustrates the problem that there are about 30 'far left' parties. The far left hasn't got more than 1% of the vote, even when the Communist Party of Great Britain has 2 MP's back in the 50s. In 2010, UKIP and the BNP got 5% of the vote between them, so even if there was a single party, it's not promising.
There are some signs of growth, the Trade Union and Socialist Coalition (TUSC) is going to put up 100 candidates in the elections this year, so there is an electoral presence, so the 'idea' of socialism may reach more people. [Edit: a major partner in the TUSC is the Socialist Party of England and Wales which traces back to militant tendency]. I doubt they will get an MP, but there is a sitting RESPECT MP (George Galloway for Bradford West by-election in 2012) and I'm happy to see the Greens got an MP last time round too (Caroline Lucas for Brighton Pavilion). This election could be full of surprises as no-one knows where it's going. but overall, it's quite a mess and only a much larger process (probably growing income inequality and awareness of it's corrosive effects) may foster the kind of conditions where people start to realize something is wrong.
In spite of that, if not because of it, it remains important to get involved in whatever way you can. anything is better than apathy at the moment. I joined the Communist Party of Britain, mainly because their programme is well thought out, a long-interest in the history and the theory and name recognition (saying "I'm a commie" is bound to get a response
). Talking about socialism of any kind openly helps as hearing a reasonable dissenting voice can make people re-think their ideas and question whether the neo-liberal consensus really stacks up. So I'm optimistic that left-wing issues will go up the agenda, but I'm unsure where that will leave us because of how resistant the system now is to change and how much political uncertainty will factor into people's calculations; we are a much more pessimistic generation compared with our counter-parts 100 or even 50 years ago. The inertia is going to take time to wear off.