Macro+Telephoto?

[majestros]

Questions first then background.

Will the Sigma f/2.8 150mm OS macro with a 1.4x teleconverter provide me with IQ close to that of a nice 2.8 70-200mm telephoto? (so i can just buy the one lens, which is easier to sell to my wife) or do I really need to pick between macro OR telephoto?

If I get a 1.4x teleconverter, should I get the Sigma one or could I get equivalent IQ from the kenko pro300 (which would then allow it to be to used with a future purchase like a 100-400mm Canon). 

Background:

I am looking to make my first expensive lens purchase.  I am relatively new to photography (10 months) but have been taking many photos and maybe even ramping up. 

I love and tend to take mostly wildlife and macro shots.  I purchased a doublet close-up filter which is great for static elements (spiders in webs, etc) but would love a true macro lens that can still capture skittish bugs like dragonflies.  I would say 90% of all of  my photos are taken at 250mm on my 55-259 lens.  I would love to take sharper shots than my current lens allows. 

I have been leaning toward the Sigma 150mm OS macro for its image stabalization and long focal length for bugs and hoping that it could double for a telephoto lens particularly, if I add a 1.4x teleconverter.  (which, at 210mm would get me close to my current 250mm)

I rented this Sigma lens and the sigma 1.4TC to go with it for a weekend and was happy with my results handholding.

I will likely eventually get a long telephoto lens (I'm thinking probably the 100-400mm Canon), and my other expensive lens on the horizon will likely be one of the 15-85 or the 17-55 2.8 Canons. 

Thanks for any adivce or thoughts!

[majestros]

Thanks ebiggs.  Yeah, I agree.  I think the TC may be out of the picture now.  I'm still trying to decide between going for the macro (as I still would really like to take macro shots) or something like the 100-400  or 300 f/4 canons for my first fancy purchase now.  Both the of the above telepohot lenses will get to 0.38x magnification hich isn;t terrible (but isn't macro obviously)

Thanks again all.

[TCampbell]

Really these decisions are all about what you'd *actually* get a lot of use out of.  What are your favorite images and what are your favorite subjects -- and then decide which lens is ideal for those types of shooting.

I own seven different lenses (it's not like you buy these all at once... it took several years to eventually collect all of these).  A few are special purpose lenses... they don't get used often unless what I need to shoot calls for that lens.  But when I do need to shoot those things, those lenses are invaluable.  

My general-purposes lenses that get a lot of use are my 24-70 and my 70-200.  I own the EF 300mm f/2.8L IS.  This is an extremely nice lens... it's also very expensive.  But it's also extremely heavy, bulky, and hardly ever gets used.  If I had it to do over, I probably would not have bought the 300mm lens.  It's only a 50% increase over the 70-200... but for wildlife I wish I had a 400mm (basically double what the 70-200 can do), but I find I don't shoot wildlife often enough to justify the purchase.  If you go above 400mm it gets very hard to track any subject that is moving because the angle of view is extremely narrow.