Hi, I just furnished my entire apartment from Ikea, and a sofa from Seg-Muller and I don't have a car. Hope this helps someone.
I go to the Brunnthal Ikea by taking the S2 to Thaulfkirchen then bus 222 is waiting. The bus runs during the week till 8:07pm, but on Saturdays only to 5ish pm. The bus ride is about 15minutes, and Ikea is the last stop.
I found a taxi that will pick me up from Ikea with a big red VW van for 25Euros flat-rate to my flat by the Marienplatz, and he even helps carry the stuff in with me. His name is Soot and phone is 666 10 888(marginal English). I had quite a few things shipped from Ikea, and the shipping fee is a min. of 20Euros, then 12% until it caps at 49 Euros, no matter how much you spend. I like using Soot better now though. Invest in a cordless drill and have patience assembling things.
Seg-Mueller is another good, large store with accessible by S6. I think the quality is better than Ikea, but more spendy too. The bottom floor stuff is more like Ikea in price. S6 stop is Grun(2 stops after Feldkirchen), and there is a store bus that takes you direct from the S6. Bus is only 5 minutes.
Kare on Senglingerstr. is good too. There are a few other stores good along that street too.
Kardst has a good furniture store located by the Oktoberfest U stop.