I prefer water based lubes as they dont usually react with toys or condoms, however like POP mentioned, it will depend on your preference. Silicone base lubes have a very silkily non-oily or sticky feel to them like some water base lubes and tend to last longer between applications but they will react with silicone toys and some finishes used on certain toys.
I've just started experimenting with high-end silicone lubes, (like Eros Bodyglide)so I'm still not sure how I feel about them, after reading up on their compatibility with high-end silicone toys (in particular, the Feeldoe). Until now, I always heard that you absolutely could not use the two together, but I started researching it and found that you can with certain products. I actually wrote to the company that makes the Feeldoe (Tantus) and asked if I could safely use Eros with it. They said it would be fine...and they were right! You just want to do a spot test on an inconspicuous place first...if it is going to cause a reaction, it will do so very quickly. But the key is, both have to be very high quality. You have to be careful because a lot of cheaper products may be marketed as silicone or something that sounds like it, but may not actually be the quality you are led to believe.