What units should I buy next?

I have a dilemma. I am unsure of what to buy next. I currently own an Archon, a Succubus, Duke, 30 wyches, 30 Kabalites, 3 Venoms, 3 Raiders, 2 Ravagers, 10 Scourges, 9 Reavers and a Razorwing. I am thinking about either a box of Incubi, another Razorwing, or another Venom. My typical list includes 2 squads of wyches in raiders with a Succubus with one squad, and either 3x5 Kabalites in Venoms, or 10-20 Kabalites in an Aegis line usually with Duke (instead of the Succubus) or 3x3 Trueborn w/ Splintercannons in Venoms. I always take at least the 2 Ravagers, most of the time the Razorwing. I have been taking detachments of Chaos Marines lately with a Sorcerer, a few Marines or Cultists, and a Vindicator. I usually don't use the Scourges, but I usually use all 9 Reavers. I usually just rush everything up the board and shoot Venoms at anything I can. Sometimes I switch the Kabalites in the Venoms for Wyches, and either take gunboats or the Kabalites in the Aegis line. Any suggestions? I suppose the closest thing my tactics could be compared to is a Venom spam, but I try to balance it out a little more.

Well, looks like a good time to expand to coven units!
But if you want to keep the kabal-cult theme, I think incubi is good.

@Kabal_of_the_Red_Shadow wrote:

I currently own an Archon, a Succubus, Duke, 30 wyches, 30 Kabalites, 3 Venoms, 3 Raiders, 2 Ravagers, 10 Scourges, 9 Reavers and a Razorwing. I am thinking about either a box of Incubi, another Razorwing, or another Venom.
Any suggestions? I suppose the closest thing my tactics could be compared to is a Venom spam, but I try to balance it out a little more.

Venom spam with only 3 venoms???  
For a balance of competitive, fun and variety I would second the Incubi recommendation.  Gives you some additional tactical options and is a fun unit.  I am really getting into models and games that use the range of DE (except of course mandrakes, I do have the models but I have never used them... I'm not sure it is allowed ).  Of course, you can't really go wrong with another venom either.  Coven are great units but not everyone is into them.  Other options may be beasts but that gets pricey quick.  I would hold off on a second razorwing as I am hoping to see the voidraven sometime this decade.  So if you aren't ready to jump on the coven theme; 1. Incubi, 2. Venom, 3. Razorwing.

Well I went to a gaming store and was planning on buying a box of Incubi and a Venom, but they didn't have either, so I bought another Razorwing and a Daemon Prince XD My birthday was yesterday however, so I think I may use some of the money I got for it to grab the Venom and Incubi. I'm looking for more competitive stuff, Deldar are my competitive army, my Chaos is my "fun" army.

I would say go into the beastmasters units.. I bought dire wolves(10 khymaraes) hellions( converted them into four beastmasters and a baron) all for 50 dollars