Hi Nematulla,
This type of question is tough to answer as different AP's are more suitable than others depending on Environment, RF Factors etc. Maybe this will help get you started;
Cisco Aironet Wireless Access Points Solution Overview
http://www.cisco.com/en/US/products/ps6108/prod_brochure0900aecd8035a015.html
We have had good luck with the following AP's;
Cisco Aironet 1130AG Series IEEE 802.11A/B/G Access Point
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Low-profile enterprise-class access point with integrated antennas for easy deployment in offices and similar RF environments.
From this doc;
http://www.cisco.com/en/US/products/ps6087/products_data_sheet0900aecd801b9058.html
Cisco Aironet 1230AG Series 802.11A/B/G Access Point
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Cisco Aironet 1230AG Series Access Points deliver the versatility, high capacity, security, and enterprise-class features demanded by WLAN customers. These IEEE 802.11a/b/g access points are designed specifically for challenging RF environments such as factories, warehouses, and large retail establishments that require the
antenna versatility associated with connectorized antennas, a rugged metal enclosure, and a broad operating temperature range.
From this doc;
http://www.cisco.com/en/US/products/ps6108/products_data_sheet0900aecd801b9068.html
Cisco Aironet 1240AG Series 802.11A/B/G Access Point
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Cisco Aironet 1240AG Series Access Points deliver the versatility, high capacity, security, and enterprise-class features demanded by WLAN customers. These IEEE 802.11a/b/g access points are designed specifically for challenging RF environments such as factories, warehouses, and large retail establishments that require the antenna versatility associated with connectorized antennas, a rugged metal enclosure, and a broad operating temperature range. The Cisco Aironet 1240AG Series provides local as well as inline power, including support for IEEE 802.3af Power over Ethernet (PoE).
From this doc;
http://www.cisco.com/en/US/products/ps6521/products_data_sheet0900aecd8031c844.html
Hope this helps!
Rob