Despite the detailed and informative post from @Raghav Nehra, there's no reason to avoid .net domains. The key is picking the right ones.
The right ones are names that are already in high demand online because many other extensions are actually being used by existing businesses. This creates scarcity, which in turns gives value to the available .net name.
You probably still won't sell a two word .net name for more than mid XXX unless it's really good (or you get lucky), so you need to buy cheap and choose wisely.
For LoveMail.net, I'm afraid I don't see anything beyond reg value, simply because there just aren't many viable online businesses operating under that name (or similar ones). I would not renew this one.