Ary

the celeron is the bottleneck there. Linux runs well on 2GB of ram as long as you don't do things that max out the ram. a lightweight distro uses about 500mb so you have 1.5gb left. you can do plenty with that. 
 
must. resist. raging.

Or I can try classical windows 8 or 8.1, because they look pretty cool and the metro design is awesome.

avoid that. it used to send telemetry (not anymore) which is a big no no in linux, also it's quite bloated because of the custom theming thing they have going on, and parts of their interface are gnome based iirc (could be wrong there), regardless it's not the lightest OS out there, and with only 2GB of ram every mb matters. 

2GB of ram is quite low even for linux. if you can upgrade it i'd recommend going up to 4gb, that'll give you some more room. then you'll actually be able to run linux and have chrome and something like spotify running at the same time. 

The only problem with Vista is that it's no longer supported, so you won't get security updates anymore. Some Linux distros are very lightweight and can run really well on old hardware, though the i5 520M isn't exactly terrible.