There is no doubt that the best place to shop for wine in Houston is Houston Wine Merchant, formerly known as Wines of America. Owner Scott Spencer can usually be found at the Shepard Square store, 2055 Westheimer, Suite 155 (713) 524 3397
Houston Wine Merchant puts out a monthly newsletter which contains sales items and wine recommendations. It also gives the schedule for their formal and informal wine tastings. Every Friday evening one can drop by the Stores and sample a select tasting of a particular vintner's offerings. This is an excellent way to "try before you buy." Also, the tasting samples are usually reduced from their regular prices.
Another nice thing about Houston Wine Merchant is that their staff is knowledgeable. This is important if you aren't sure what you need. Tell them what you have liked in the past and they will be happy to make current recommendations. You can also visit the Houston Wine Merchant website.
Houston Wine Merchant get my highest praise.
The largest selection of wines in Houston is at the downtown Spec's Liquor Warehouse (2410 Smith, 713-526-8787). The number of wines they carry is phenomenal. Specs almost always has the best "non-sale" prices in Houston. It is a great place to go if you know what you want. Spec's often has write-ups on various wines taped just above a particluar wine. Be aware that these write-ups (from such sources as Wine Spectator) are sometimes for a vintage year other than the one they have in stock. Pay attention. Specs also has a lower price for cash purchases. Checks and debit cards count as cash. The savings is usually 5%. Case discounts are also offered if you but a case of a particular wine. Case discounts usually run 10%. To determine if Spec's sells the wine you are looking for, visit the Spec's website.