Doing things differently...need some input

So I've recently started collecting DE (marines are my first love of 40k) and need to fill out my Elites and 2 Heavy Support Choices...I'm trying to get a full force org chart collected. Thus far I have 2 hqs (archon and lelith), 3 wych squads, 3 warrior squads (all envisioned to have raiders eventually), 9 man reaver squad, 10 man scourage squad, and 10 man hellion squad...oh and a razorwing. Essentially I bought 3 battleforce boxes and goodies that looked fun to play with!

Now I look to fill my Elites and last 2 heavy support choices...I've been debating heavily over what to use for elites...and damn its hard to choose as well as my HS. I've been thinking lets go with ravagers because I face a lot of tanks (IG tank spam and blob squads...though I do face some other stuff like Eldar and a tiny bit of allied GK) usually and I could use the anti-tank...but I was thinking what if I did things differently.

Let me get to my long drawn out point...thoughts on filling my last slots:
2x Talos Pain Engine/Cronos
2x Blasterborn in Venoms
1x 4man squad of grots to pair with Lelith in a raider

The idea is to show some high toughness targets that can kick some serious ass while allowing me to get close with grots, wyches and the like to take out tanks, infantry etc...if things go well everyone gets close and I just assault things, use wyches as fodder where needed for dangerous overwatching units, etc.

My questions are: What are your thoughts on this kind of army? What mix would you choose for the talos/cronos and why? Would you choose 2 blasterborn or something else, like incubi or even something different such as different special weapons, etc? How would you tool out any of these units as well.

I'm really looking to have a fun army that isn't the same as everyones max 3 ravagers, etc...I'm trying to do things a little differently...though I'll admit everyone uses blasterborn...I just figure I might need some venoms and extra pure anti tank.

Thanks all,
Ligs

Here's a couple of links links to my blog where I look at the synergy of the various options in the heavy and elite sections of the codex and how they work with the unit or the army as a whole.

Elites
Heavy Support

thank you for your input, by the look of what you have written, it seems like the grots and pain engines would go well together with all the assullty stuff I have

any one else have any input?