No but seriously - I wouldnt see any issues with what you propose - however this depends on how many caps there are to replace.
You always want to maintain or exceed the voltage rating - and you can generally safely exceed the uF rating.
If you upgrade the value of power supply caps you also need to consider that the power-on surge will increase, and this will put extra strain on your rectifier bridge & power switch contacts. Keep that in mind if you do this.