Kate, my melee team is feral druid tank with 3 rets and an enhancement shammie. Previously I have run a 4 shammie, 1 DK team and also have a mixed caster team with pally tank.

I can definitely recommend the druid tank/enh shammy addition to the pallys. For PvP my 4900ish PvP geared shammy still gets smashed fairly quickly and I really miss not having Death Grip in the group for PvP, so my ultimate goal here is to switch the DK to the melee group with 4 rets still.

For PvE however the group is awesome. I have +130 resist to anything I need. The druid tank has been super easy to gear up well, given that PvP gear is often best in slot for tanking also and seems infinitely more hardy with 4900GS than my 5800GS DK tank. As enhance the shammy will generally outdps my rets on single targets and can keep up with a bit of extra mana use on aoe. For flexibility I can also switch him to resto and have what I think is the best compromise between good group healing and tank healing in a single class. I use a repeater region setup for healing which means I just spam my dps/tank keys and click for chain heals/riptides as required.

The passive healing with this setup is also brilliant. Imp MotW, Healing stream totem, judgement of light, divine storm etc. Finally on top of this I get melee buffs of 5% crit, 20% haste, 10%atk pwr, blessing of kings and might.

When it all comes down to it though, pick the combo that you have the most fun with. If you are not having fun with your pallies anymore then by all means look at different options and see what appeals to you the most.