Recently almost all the major handset manufacturers agreed to use micro-USB as the standard charger interface in the EU for all new phones. Likely this will become a worldwide standard as there is little benefit in manufacturing a different model in different parts of the world.
Whilst I think this is a great move (to have a standardized charger/data interface), the choice of micro-USB I am not totally sold on. I have had the pleasure to regularly use 3 different Android devices over the last couple of years, one with mini-USB and two with micro-USB. None of these have been perfect, but the micro-USB seems to have provided more issues, especially in the sense of a loose connection.
Initially I though this loose connection was an issue caused by the USB socket on the phone getting worn over time. This was the conclusion reached after buying a few different replacement cables from eBay. They would only charge if pressure was placed on the cable (i.e. bending it down with the screen facing up) and rarely would data connectivity be achieved. This conclusion was further solidified after buying a new handset and having the same issue with the same cables.
So the first point to note here is that not all micro-USB cables are the same (even though it is a standard) and the fact that perhaps some phones are more fussy about what cables are used. The new phone I was testing was an HTC Incredible S. The HTC cable that came with the phone worked perfectly (although still felt a bit loose), but the range of eBay cables all had issues.
After a bit of searching at the local office supplies store, I found a micro USB cable supplied by Nokia that looked like it had slightly bigger teeth on it than the other cables. After buying one of these cables I confirmed that it also worked perfectly (like the stock HTC cable).
So the takeaway here is, steer away from the cheapo eBay cables and get a Nokia, HTC or other manufacturer cable. You can pick up the Nokia cables on eBay pretty cheap, just look out for the cable clip that comes with the genuine ones, but not the knock offs.